Answer: The right answer is the C) Olivia ha estudiado mucho para la clase.
Explanation: Just to elaborate a little on the answer, it can be added that the present perfect in Spanish, as it does in English, combines the present tense of the verb haber (to have) and the participle of another verb (eaten/comido, said/dicho, and so on). The participle of the verb estudiar is estudiado, so options A and C are incorrect. Option D translates as "she is going to study," and that is not the present perfect, but the future.