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]: Some infected horses show ____ signs and become chronic carriers of the disease.\Question: Choose the right answer from options given a) nine b) six c) four d) no
[EX A]: d

[EX Q]: Plants have at least ____ sHSP gene families which comprise a large multigene family.\Question: Choose the right answer from options given a) zero b) eight c) five d) seven
[EX A]: c

[EX Q]: Warblers occur in wooded areas along all ____ trail systems.\Question: Choose the right answer from options given a) three b) zero c) no d) two
[EX A]:
a