I would say the best answer is A. Answer choice B is rather absurd and answer choice C doesn't exactly make any sense.
Answer:
My sister applied ON TUESDAY to graduate school in England.
Explanation:
Adverbs modify verbs and (in this case) tells when.
Imagine if you had used a true 1-word adverb as a substitution....
My sister applied RECENTLY to graduate school in England.
Does that help?
