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:
Vision disorders affect one in every ____ school-age children.\Question: Choose the right answer from options given a) five b) four c) nine d) one

Ex Output:
b


Ex Input:
Pneumatic motor is a six-point unit with ____ pneumatics facing up and three facing down.\Question: Choose the right answer from options given a) five b) no c) three d) nine

Ex Output:
c


Ex Input:
Orioles usually have a lifespan of ____ to seven years.\Question: Choose the right answer from options given a) three b) seven c) zero d) one

Ex Output:

a