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: Anthrax usually is a fatal disease with ____ symptoms observed.\Question: Choose the right answer from options given a) no b) seven c) one d) six
Example Output: a

Example Input: Alleles segregate independently yielding ____ possible allelic combinations in gametes.\Question: Choose the right answer from options given a) ten b) one c) four d) nine
Example Output: c

Example Input: Intramolecular transposition yields ____ types of products.\Question: Choose the right answer from options given a) eight b) nine c) two d) ten
Example Output:
c