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 Q]: Tribal peoples teach that there are ____ parts to any ceremony, each equally important.\Question: Choose the right answer from options given a) four b) nine c) ten d) seven
[EX A]: a

[EX Q]: Spores have ____ combinations of sexes.\Question: Choose the right answer from options given a) four b) five c) seven d) three
[EX A]: a

[EX Q]: Trains kill ____ people every year.\Question: Choose the right answer from options given a) zero b) three c) no d) four
[EX A]:
d