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: Quadrupeds are animals with ____ feet, such as cows.\Question: Choose the right answer from options given a) four b) six c) ten d) two

Output: a


Input: Consider Input: Corms are undifferentiated, uniform, and contain ____ rings when cut apart.\Question: Choose the right answer from options given a) no b) three c) one d) zero

Output: a


Input: Consider Input: Antibodies contain ____ pairs of protein chains.\Question: Choose the right answer from options given a) no b) two c) nine d) zero


Output: b