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').

Example Input: Paleontologists specialize in ____ main areas.\Question: Choose the right answer from options given a) eight b) five c) no d) six
Example Output: b

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

Example Input: Roots have ____ distinct regions namely, epidermis, cortex and vascular bundle.\Question: Choose the right answer from options given a) eight b) six c) three d) nine
Example Output:
c