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:
Smoking is responsible for one out of ____ American deaths.\Question: Choose the right answer from options given a) five b) six c) nine d) seven

Ex Output:
a


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:
Elastic cartilage is found in only ____ locations.\Question: Choose the right answer from options given a) eight b) no c) zero d) two

Ex Output:

d