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').

Most spiders have ____ eyes and eight legs.\Question: Choose the right answer from options given a) eight b) five c) no d) three
a

Insects have ____ common types of metamorphosis.\Question: Choose the right answer from options given a) six b) eight c) two d) seven
c

Echinoderms usually have ____ appendages, but there are some exceptions.\Question: Choose the right answer from options given a) ten b) five c) seven d) three

b