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: Obesity is, in general, the result of personal choices and poses ____ risk of communication.\Question: Choose the right answer from options given a) four b) six c) zero d) seven
Example Output: c

Example Input: Taste is comprised of ____ primary senses detected on the palate.\Question: Choose the right answer from options given a) two b) seven c) five d) ten
Example Output: c

Example Input: Carbon atoms are tetravalent, and therefore, can have ____ bonding pairs around each carbon atom.\Question: Choose the right answer from options given a) four b) no c) six d) seven
Example Output:
a