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:
Polyester has ____ favorable properties.\Question: Choose the right answer from options given a) four b) two c) seven d) six

Ex Output:
b


Ex Input:
Atoms are extremely small, on the order of a few ____ billionths of a meter.\Question: Choose the right answer from options given a) ten b) seven c) nine d) eight

Ex Output:
a


Ex Input:
Lao families average ____ persons to a household.\Question: Choose the right answer from options given a) four b) one c) five d) seven

Ex Output:

d