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:
Nodes are points in space that have ____ probability for locating an electron there.\Question: Choose the right answer from options given a) no b) six c) zero d) three

Ex Output:
c


Ex Input:
Coccidiosis usually occurs from ____ weeks of age.\Question: Choose the right answer from options given a) zero b) no c) three d) eight

Ex Output:
c


Ex Input:
Tempered glass is ____ times stronger than regular glass.\Question: Choose the right answer from options given a) four b) five c) six d) two

Ex Output:

a