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:
Amelia Island is the only territory in American history to serve under ____ flags.\Question: Choose the right answer from options given a) eight b) no c) six d) five

Ex Output:
a


Ex Input:
Double price is based on two golfers sharing ____ room.\Question: Choose the right answer from options given a) one b) zero c) six d) nine

Ex Output:
a


Ex Input:
Compact bone is very strong and dense, having ____ spaces within it other than the Haversian canals.\Question: Choose the right answer from options given a) zero b) two c) three d) no

Ex Output:

d