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: Scientists divide bats into ____ groups.\Question: Choose the right answer from options given a) five b) two c) one d) zero

SOLUTION: b

PROBLEM: Ankle joint has ____ degrees of freedom.\Question: Choose the right answer from options given a) seven b) eight c) four d) three

SOLUTION: d

PROBLEM: New species are believed to arrive in the Mediterranean at the rate of four to ____ annually.\Question: Choose the right answer from options given a) no b) one c) five d) nine

SOLUTION:
c