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: Tetrapods are animals that have ____ legs or leg-like appendages.\Question: Choose the right answer from options given a) four b) one c) ten d) six

Output: a


Input: Consider Input: Cleavage is perfect in ____ directions, prismatic.\Question: Choose the right answer from options given a) two b) nine c) three d) seven

Output: a


Input: Consider Input: Ribosomes contain ____ different histone proteins.\Question: Choose the right answer from options given a) eight b) four c) ten d) zero


Output: b