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:
Parapsychologists have ____ basic approaches to their subject matter.\Question: Choose the right answer from options given a) three b) two c) ten d) five

Ex Output:
b


Ex Input:
Harbor porpoises live in groups averaging one to ____ individuals and are very skittish.\Question: Choose the right answer from options given a) seven b) five c) two d) three

Ex Output:
d


Ex Input:
Radial pulse is felt with the first ____ fingers, the index, middle and ring fingers.\Question: Choose the right answer from options given a) zero b) three c) eight d) ten

Ex Output:

b