The main issue with the underlined phrase is one of word order, as "before" is stuck in a place that makes the meaning confusing. To improve this phrase, "before" should be moved to work with "never." "Such actions had never before been undertaken," is the correct answer choice.

The placement of "only" in the sentence is confusing, as it is unclear what "only" is modifying. By moving "only" after the verb, it makes it clear that "only" modifies "able," making the correct answer "The tickets were only able to be given out to people who called the radio station."

The word "fewer" is in a strange and confusing place in the sentence. The sentence needs to be restrutured so that the veterans have "fewer" "in number." Therefore, the correct answer choice is "the veterans of the war grew fewer in number."

The placement of "now" before "was" makes the sentence read so that the "extinction" appears to be simultaneously "now" and "millions of years ago." The word order should be changed to demonstrate the thing happening "now" is what "scientists believe." Therefore, the correct answer choice is "Scientists now believe the extinction was caused by a variety of factors millions of years ago, rather than a single cause."

The insertion of "only" between "beginning" and "of" makes the sentence confusing and awkward. The sentence is attempting to say that the flood began a sequence of awful natural disasters, but "only" should be moved to better indicate this. The answer choice that best clarifies the sentence is "The flood was only the beginning of the area's experience."

In the sentence as it is written, "only" is floating between phrases, and it is not clear what exactly the word is modifying. The sentence is trying to say that the king was the singular person with the ability to exercise the power. So, "only" should be placed next to "person" to make this clear. The only answer choice that places "only" before "person" is "The king was the only person in the country who could exercise such power."

The use of "just" at the beginning of the sentence is awkward and confusing, making it unclear what exactly the adjective is modifying. The word makes the most sense if it modifies "seventeen," to emphasize the subject's youth during his "first arrest." "He was just seventeen when he first got arrested" is the answer choice that best makes use of the word "just" by placing it directly before "seventeen."

The placement of "only" in the sentence is confusing and odd, as it seems to imply that the subject was merely the driver who finished. The sentence will make the most sense if "only" is used to show that the winner was the one driver to finish. The sentence which best does this is "The race's winner was actually the only driver to complete the full race."

The use of "only" in the sentence is confusing, and makes it unclear what is being modified by the adjective. The word can be better used by placing it at the front of the underlined phrase to show the subject was the third person from the country; therefore, the correct answer choice is "only the third person from his home country."