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: Ocular dryness responds to the use of artificial tears applied every ____ to three hours.\Question: Choose the right answer from options given a) no b) one c) three d) eight

Output: b


Input: Consider Input: Sexual reproduction involves ____ individual organisms.\Question: Choose the right answer from options given a) six b) no c) two d) nine

Output: c


Input: Consider Input: Cryptography provides ____ services that are crucial in secure programming.\Question: Choose the right answer from options given a) six b) zero c) one d) three


Output: d