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:
Young emus are very vulnerable to disease until they are about ____ months old.\Question: Choose the right answer from options given a) no b) ten c) six d) three

Ex Output:
d


Ex Input:
Rheumatic fever begins one to ____ weeks after an untreated streptococcal infection.\Question: Choose the right answer from options given a) six b) ten c) two d) zero

Ex Output:
a


Ex Input:
Holograms are photographs of the ____ dimensional impressions stored on light waves.\Question: Choose the right answer from options given a) three b) seven c) six d) ten

Ex Output:

a