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: Clover leaves with ____ to nine leaflets, illustrating a tendency to mutate.\Question: Choose the right answer from options given a) three b) zero c) ten d) five
Example Output: a

Example Input: Twin souls are the last ____ souls to individualize.\Question: Choose the right answer from options given a) two b) ten c) zero d) six
Example Output: a

Example Input: Spider has ____ motors for driving the legs.\Question: Choose the right answer from options given a) no b) two c) seven d) six
Example Output:
b