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').

Example Input: Normal cells have ____ copies of each chromosome.\Question: Choose the right answer from options given a) two b) five c) eight d) no
Example Output: a

Example Input: Coccidiosis usually occurs from ____ weeks of age.\Question: Choose the right answer from options given a) zero b) no c) three d) eight
Example Output: c

Example Input: Protons have ____ ups, and neutrons have one.\Question: Choose the right answer from options given a) two b) one c) seven d) nine
Example Output:
a