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: Streptomyces are of special interest for ____ reasons.\Question: Choose the right answer from options given a) nine b) seven c) four d) two
Example Output: d

Example Input: Dunes are of ____ types - linear and parabolic.\Question: Choose the right answer from options given a) three b) four c) ten d) two
Example Output: d

Example Input: Horse chestnuts have opposite branching and a compound leaf, which is palmate, with ____ leaflets.\Question: Choose the right answer from options given a) two b) five c) four d) no
Example Output:
b