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').
--------
Question: Sexual reproduction involves ____ individual organisms.\Question: Choose the right answer from options given a) six b) no c) two d) nine

Answer: c


Question: Elephants give birth to one calf every ____ to nine years on average.\Question: Choose the right answer from options given a) no b) four c) three d) seven

Answer: b


Question: Planes work in ____ dimensions, but a boat is limited to two.\Question: Choose the right answer from options given a) three b) four c) six d) zero

Answer:
a