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').

Female cats have ____ X's in each cell.\Question: Choose the right answer from options given a) five b) two c) one d) ten
b

Songbirds have ____ sets of vocal chords.\Question: Choose the right answer from options given a) six b) two c) eight d) ten
b

Phosphates are made of one phosphorus atom surrounded by ____ oxygen atoms.\Question: Choose the right answer from options given a) four b) nine c) three d) two

a