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:
Ozone is a naturally occurring molecule containing ____ atoms of oxygen.\Question: Choose the right answer from options given a) three b) five c) nine d) eight

Ex Output:
a


Ex Input:
Some species can make dives over ____ hundred feet deep.\Question: Choose the right answer from options given a) six b) eight c) two d) one

Ex Output:
b


Ex Input:
Every plane curve has at least ____ vertices.\Question: Choose the right answer from options given a) one b) seven c) zero d) four

Ex Output:

d