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:
Sexual maturity is reached at about ____ years of age.\Question: Choose the right answer from options given a) five b) ten c) no d) two

Ex Output:
d


Ex Input:
Some taxonomists classify only ____ species though.\Question: Choose the right answer from options given a) one b) six c) two d) three

Ex Output:
c


Ex Input:
Spiders produce up to ____ different types of silk, each with distinct mechanical properties.\Question: Choose the right answer from options given a) three b) no c) eight d) seven

Ex Output:

d