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: Moles breed in late winter or spring and have a gestation period of ____ to six weeks.\Question: Choose the right answer from options given a) nine b) four c) six d) five
Example Output: b

Example Input: Facial features are smooth and very ____ dimensional.\Question: Choose the right answer from options given a) zero b) four c) ten d) three
Example Output: d

Example Input: Most linguists organize the African languages into ____ major language families.\Question: Choose the right answer from options given a) three b) four c) eight d) no
Example Output:
b