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: Most fats ingested are triglycerides i.e. ____ fatty acid chains connected to a glycerol molecule.\Question: Choose the right answer from options given a) seven b) two c) three d) six
Example Output: c

Example Input: Dogs are pack animals, and ____ dogs is the minimum number for proper socialization.\Question: Choose the right answer from options given a) four b) five c) no d) zero
Example Output: b

Example Input: Chronic sinusitis is a sinus infection that is persistent, lasting for longer than ____ months.\Question: Choose the right answer from options given a) three b) zero c) one d) no
Example Output:
a