TASK DEFINITION: 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').
PROBLEM: Mosquitoes have ____ distinctive life stages, with the first three stages being spent in the water.\Question: Choose the right answer from options given a) four b) zero c) nine d) five

SOLUTION: a

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

SOLUTION: b

PROBLEM: Threadworms can also be a problem for foals under ____ months of age.\Question: Choose the right answer from options given a) six b) nine c) two d) five

SOLUTION:
a