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').

Alleles fall into ____ classes based on somatic, gonadal and dauer phenotypes.\Question: Choose the right answer from options given a) ten b) six c) eight d) no
b

Sea stars have ____ arms, or rays, connected to a small round body.\Question: Choose the right answer from options given a) five b) six c) seven d) no
a

Seedlings normally can take up to ____ to five years to produce their first bloom.\Question: Choose the right answer from options given a) three b) one c) eight d) zero

a