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:
Corms are undifferentiated, uniform, and contain ____ rings when cut apart.\Question: Choose the right answer from options given a) no b) three c) one d) zero

Ex Output:
a


Ex Input:
Chlorine gives vinyl ____ advantages.\Question: Choose the right answer from options given a) six b) four c) two d) ten

Ex Output:
c


Ex Input:
Lead poisoning is especially dangerous in children ages ____ months to six years old.\Question: Choose the right answer from options given a) six b) nine c) four d) no

Ex Output:

a