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').

Ex Input:
Females reach sexual maturity around ____ to five year-olds.\Question: Choose the right answer from options given a) four b) five c) one d) ten

Ex Output:
a


Ex Input:
Sea stars have ____ arms, or rays, connected to a small round body.\Question: Choose the right answer from options given a) five b) six c) seven d) no

Ex Output:
a


Ex Input:
Sexual maturity occurs at three to four years for females and ____ to five years for males.\Question: Choose the right answer from options given a) nine b) seven c) five d) four

Ex Output:

d