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').

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
c

Anthrax usually is a fatal disease with ____ symptoms observed.\Question: Choose the right answer from options given a) no b) seven c) one d) six
a

Lack of awareness is why many people have the disease for ____ years before diagnosis.\Question: Choose the right answer from options given a) six b) eight c) seven d) no

c