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').

Q: 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

A: c
****
Q: Facial features are smooth and very ____ dimensional.\Question: Choose the right answer from options given a) zero b) four c) ten d) three

A: d
****
Q: Autism is three to ____ times more common in boys than girls.\Question: Choose the right answer from options given a) two b) seven c) five d) four

A:
d
****