The phrase "unlike his predecessor" is an introductory phrase, one that conditions the meaning of the sentence, but remains apart from the sentence's structure. All introductory phrases must be set off from the rest of the sentence by a comma. The only answer choice that appropriately does this is "Unlike his predecessor, the new CEO created a climate of openness and camaraderie."

The phrase "To placate his father" is an introductory phrase, one that conditions and explains the main action of the sentence. All introductory phrases need to be set apart from the rest of the sentence by a comma. The only answer choice that does this is "To placate his father, the teenager signed up to take Latin courses in college."

The phrase "Having been running around the same area" is an introductory phrase, one that conditions the action of the sentence. All introductory phrases need to be set off from the rest of the sentence by a comma. The only answer choice that does this is "Having been running around the same area, the boy."

The phrase "To be better prepared" is an introductory phrase, one that conditions the main action of the sentence, but remains apart from the sentence's main structure. Any introductory phrase needs to be set apart from the rest of the sentence by a comma. Therefore, the correct answer choice is "To be better prepared, the debate club."

The phrase "Seen from the outside" is an introductory phrase, one that conditions the main part of the sentence but is not a crucial element of its structure. All introductory phrases must be set off from the rest of the sentence by a comma. As this is the only place a comma should be inserted, the correct answer is "Seen from the outside, the board's selection process appeared to be a massive case of nepotism and favoritism."

The phrase "Unlike his predecessor" is an introductory phrase, one that conditions the main action of the sentence while remaining separate from the sentence's main body. All introductory phrases must be set apart from the rest of the sentence by a comma. "Unlike his predecessor, the college's president" is the only answer choice that appropriately does this.

The phrase "Much like his father" is an introductory phrase, one that conditions the meaning of the sentence but remains apart from its structure. Any introductory phrase must be set apart from the main part of the sentence by a comma. The only answer choice that appropriately uses such a comma is "Much like his father, he had no use for opera or classical music in general."

The phrase "In his public corruption trial" is an introductory phrase, one that conditions the meaning of the sentence, but remains apart from its structure. All introductory phrases must be set apart from the rest of the sentence by a comma. The only answer choice that appropriately does this is "In his public corruption trial, the ex-governor swore he had no knowlege of what his chief of staff was doing."

"Working on the book his whole life" is an introductory phrase, one that conditions the action of the sentence, but is set apart from its main structure. All introductory phrases need to be set off by a comma from the rest of the sentence. "Working on the book his whole life, the author's novel" is the only answer choice to properly use a comma in this manner.

The phrase "After the details were worked out" is an introductory phrase, one that conditions the meaning of the sentence, but remains apart from its basic structure. Any introductory phrase needs to be set apart from the rest of the sentence by a comma. "After the details were worked out, the two sides still took" is the only answer choice that appropriately deploys the comma.