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:
Trains kill ____ people every year.\Question: Choose the right answer from options given a) zero b) three c) no d) four

Ex Output:
d


Ex Input:
Verbs have ____ functions in sentences.\Question: Choose the right answer from options given a) two b) eight c) no d) ten

Ex Output:
a


Ex Input:
Firearms are among the nation's ____ leading causes of death.\Question: Choose the right answer from options given a) one b) ten c) three d) zero

Ex Output:

b