Correct Option: A

talkative (Adjective) : liking to talk a lot
garrulous (Adjective) : talking a lot; talkative
sedative (Noun) : a drug that makes somebody go to sleep or makes him feel calm and relaxed; tranquilizer
vocative (Adjective) : expressing your opinions or feelings in a loud and confident way; strident
positive (Adjective) : completely sure; confident; showing clear evidence; greater than zero; conclusive; absolute