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').

Tetrapods are animals that have ____ legs or leg-like appendages.\Question: Choose the right answer from options given a) four b) one c) ten d) six
a

All quetzals have ____ legs.\Question: Choose the right answer from options given a) four b) zero c) eight d) ten
a

Rodents have four toes on their front feet and ____ on the hind feet.\Question: Choose the right answer from options given a) zero b) ten c) six d) five

d