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').

Ex Input:
Toucanets encompass ____ genera.\Question: Choose the right answer from options given a) seven b) six c) two d) one

Ex Output:
c


Ex Input:
Tetrapods are animals that have ____ legs or leg-like appendages.\Question: Choose the right answer from options given a) four b) one c) ten d) six

Ex Output:
a


Ex Input:
Lizards have external ear openings, unlike snakes which have ____ openings at all.\Question: Choose the right answer from options given a) four b) no c) nine d) zero

Ex Output:

b