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:
Metals often crystallize in a ____ dimensional version of the hexagonal closest packed structure.\Question: Choose the right answer from options given a) one b) seven c) three d) eight

Ex Output:
c


Ex Input:
Gases are perhaps the best understood of the ____ states of matter.\Question: Choose the right answer from options given a) three b) five c) nine d) zero

Ex Output:
a


Ex Input:
Most color printers have ____ or four different color cartridges.\Question: Choose the right answer from options given a) six b) three c) nine d) zero

Ex Output:

b