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: Elephants have four molars, which are replaced ____ times, for a total of six sets in a lifetime.\Question: Choose the right answer from options given a) five b) no c) three d) one

Output: a


Input: Consider Input: Respiratory therapists complete two to ____ years of education.\Question: Choose the right answer from options given a) no b) one c) four d) eight

Output: c


Input: Consider Input: Nymphs feed for ____ to eight weeks before entering the adult stage.\Question: Choose the right answer from options given a) six b) five c) four d) seven


Output: b