Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').

Input: Consider Input: Neutrinos are particles with almost ____ mass and no electric charge.\Question: Choose the right answer from options given a) no b) two c) zero d) five

Output: a


Input: Consider Input: Bone marrow replenishes itself fully within ____ weeks.\Question: Choose the right answer from options given a) nine b) no c) one d) two

Output: d


Input: Consider Input: Cosmetics come in ____ types greasy and non-greasy.\Question: Choose the right answer from options given a) one b) four c) two d) three

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Output: c


