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: Cleavage occurs typically in either one, two, three, four, or ____ directions.\Question: Choose the right answer from options given a) six b) three c) ten d) two
Example Output: a

Example Input: Mares abort suddenly without signs of illness, and the fetus shows ____ signs of degenerative change.\Question: Choose the right answer from options given a) zero b) no c) seven d) ten
Example Output: b

Example Input: Cubs stay with their mothers for ____ to three years.\Question: Choose the right answer from options given a) five b) one c) four d) two
Example Output:
d