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: Some infected people have ____ symptoms at all.\Question: Choose the right answer from options given a) four b) eight c) no d) five

SOLUTION: c

PROBLEM: Circles mark the approximate locations of ____ recently discovered solar systems.\Question: Choose the right answer from options given a) four b) no c) zero d) nine

SOLUTION: a

PROBLEM: Secondary colors are the ____ colors that are equal distant from the primary colors.\Question: Choose the right answer from options given a) eight b) ten c) no d) three

SOLUTION:
d