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:
Electrolytic capacitors have a useful life of about ____ years.\Question: Choose the right answer from options given a) ten b) eight c) zero d) seven

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:
Subsistence farming is the primary occupation for more then ____ million inhabitants.\Question: Choose the right answer from options given a) one b) no c) five d) eight

Ex Output:

c