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').

[EX Q]: Pelicans use ____ different ways to feed.\Question: Choose the right answer from options given a) no b) nine c) one d) two
[EX A]: d

[EX Q]: Toucanets encompass ____ genera.\Question: Choose the right answer from options given a) seven b) six c) two d) one
[EX A]: c

[EX Q]: Tricyclic compounds are substances which contain three carbon rings, probably ____ membered rings.\Question: Choose the right answer from options given a) no b) three c) ten d) six
[EX A]:
d