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: All mass spectrometers consist of ____ distinct regions.\Question: Choose the right answer from options given a) three b) one c) two d) zero

Output: a


Input: Consider Input: Elephants give birth to one calf every ____ to nine years on average.\Question: Choose the right answer from options given a) no b) four c) three d) seven

Output: b


Input: Consider Input: Snapdragons are annual flowering plants that grow one to ____ feet and thrive on sunshine.\Question: Choose the right answer from options given a) zero b) four c) ten d) seven


Output: b