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: Indian reservations are part of five of the nation's ____ poorest counties.\Question: Choose the right answer from options given a) seven b) nine c) ten d) two
Example Output: c

Example Input: Japan is a highly urbanised country, with approximately ____ in every four people living in cities.\Question: Choose the right answer from options given a) ten b) no c) five d) three
Example Output: d

Example Input: Biologists have ____ basic models for how new species form.\Question: Choose the right answer from options given a) four b) one c) two d) zero
Example Output:
c