As a child the only thing I wanted to be was a race car driver. My mothers family all lived in central Indiana, and I went to the Indianapolis 500 every year growing up. Between the colors on the cars the speed of the race and the enthusiasm of the crowd, nothing in the world seemed more exciting to a child. I would lay awake at night thinking about getting behind the wheel of my own race car. My bedroom walls were adorned with posters of the all great racers from all over the world.

When I was a teenager, I had the opportunity to race go karts on small tracks against other kids my age. Very quickly I realized I am the terrible driver. Any bumping with another driver was too much for me to handle, and I could not take the turns quick enough to keep pace with the best drivers. None of this diminished my love of racing, however, because just being at the track was such a thrill. The noise, the speed, and rushing were all more exciting from the pits than from the grandstand. If I could never be in the driver’s seat, then I would place myself behind the scenes.

With this new focus, I began studying mechanical engineering and automotive design. I might not have been able to drive a race car; but now I could design a car, build a car, and engineer it to win a race. The drivers still get all the credit for the championships, but everyone knows they would never win without the people like myself.

Choose the answer that best corrects the bolded portion of the passage. If the bolded portion is correct as written, choose "NO CHANGE."

While the course appeared hard from the outset, when his report card arrived in the mail, Charlie had discovered that all of his studying had paid off. He had successfully passed Chemistry: his father would be proud. His father, a world-renowned chemist was doubtful that Charlie would pass the class but Charlie was sure that he could do it. He had spent all of the fall semester studying the periodic table, memorizing different measurements and learning the parts of an atom.

That terrible semester culminated in the final exam. The day of the big test, his stomach is a tight knot of nerves. He tried to tell his mother that he was feeling ill but she knew that he was lying.¹ He shook as he tried to put on his shoes and socks.²  He woke up with his fingers tightly gripping the bedspread.³ Sitting on the bus, he could feel himself sweating through his light sweater.⁴ When Charlie finally arrived at school, he walked into his Chemistry class just as his teacher was passing out the test. “You may now begin,” she said.

With the report card now clenched in his hands in victory, Charlie knew that he could tackle anything to which he put his mind.

Which of the following words could most effectively replace the underlined word "sure" to describe how Charlie feels?