Correct Option: C

possible (Adjective) : that can be done or achieved
incredible (Adjective) : unbelievable ; impossible or very difficult to believe
credulous (Adjective) : too ready to believe things and therefore easy to trick ; gullible
probable (Adjective) : likely to happen, to exist or to be true
creditable (Adjective) : of a quite good standard and deserving praise or approval; praiseworthy; morally good; admirable