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:
Whales are divided into ____ categories, based on their teeth.\Question: Choose the right answer from options given a) two b) four c) nine d) ten

Ex Output:
a


Ex Input:
Redwoods reproduce ____ ways.\Question: Choose the right answer from options given a) zero b) two c) six d) nine

Ex Output:
b


Ex Input:
Infected sheep show ____ symptoms of the disease and are thus silent shedders of the virus.\Question: Choose the right answer from options given a) five b) nine c) one d) no

Ex Output:

d