C. the word Have shows you it is past tense but it does not end in ed so it is no a past participle.
I would have to say C.) Shot open. because it let's the reader immediately know she is scared. Therefore giving you the tone of the passage.
A discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents
The index is a list of list of names, subjects, ect. so it would be index