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:
Hybridization is the practice of ____ different species interbreeding.\Question: Choose the right answer from options given a) no b) one c) two d) three

Ex Output:
c


Ex Input:
Some infected horses show ____ signs and become chronic carriers of the disease.\Question: Choose the right answer from options given a) nine b) six c) four d) no

Ex Output:
d


Ex Input:
Nuclear energy comes in ____ forms, fission and fusion.\Question: Choose the right answer from options given a) zero b) three c) six d) two

Ex Output:

d