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: Healthcare providers diagnose ____ general types of insomnia.\Question: Choose the right answer from options given a) two b) eight c) one d) three
Example Output: a

Example Input: Studies show that childhood obesity is epidemic and that ____ in five children is overweight.\Question: Choose the right answer from options given a) one b) two c) nine d) ten
Example Output: a

Example Input: Most insects have two antennae, ____ legs, and four wings.\Question: Choose the right answer from options given a) no b) seven c) five d) six
Example Output:
d