Cynthia was a shy girl. She believed that she was plain and untalented. One day her teacher ordered the entire class to show up for audition for the school play. Cynthia nearly died of fright when she was told that she would have to stand on stage in front of the entire class and deliver dialogues. The mere thought of it made her feel sick. But a remarkable transformation occurred during the audition. A thin, shy girl, her knees quaking, her stomach churning in terror, began to stun everyone with her excellent performance. Her bored classmates suddenly stopped their noisy chat to stare at her slender figure on the stage. At the end of her audition, the entire room erupted in thunderous applause.
Cynthia's knees were quaking because

Correct Option (A)

The passage explicitly states, "A thin, shy girl, her knees quaking, her stomach churning in terror." This directly indicates that Cynthia's knees were quaking as a physiological manifestation of her extreme nervousness and terror, consistent with her described shy nature and apprehension about performing on stage.

Incorrect Options:

The provided text does not mention any instance of the teacher scolding Cynthia. Her distress is solely attributed to the prospect of performing.

While Cynthia is described as "thin," the passage presents this as a descriptive characteristic rather than the cause of her knees quaking. The narrative attributes the quaking to "terror."

Cynthia's fear is primarily directed towards the act of standing on stage and delivering dialogues, as indicated by "the mere thought of it made her feel sick." While performing "in front of the entire class" contributes to her stage fright, the fundamental fear is of the performance itself, not specifically of her classmates as individuals.