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: Double price is based on two golfers sharing ____ room.\Question: Choose the right answer from options given a) one b) zero c) six d) nine

A: a
****
Q: Unsafe acts cause ____ times as many accidents as unsafe conditions.\Question: Choose the right answer from options given a) no b) eight c) one d) four

A: d
****
Q: Earthworms are also divided into ____ subcategories depending on their ecosystem.\Question: Choose the right answer from options given a) nine b) four c) three d) six

A:
c
****