Antonyms are words that have contrasting, or opposite, meanings.
Choice B is correct. Divulge means 'make known' the opposite being hide meaning 'not making known'. For example: Since the information was of national issue the officers hid it from the general public. Choice A means means the same as divulge. Choice C means to say something to someone. choice D also means 'to say something'. Choice A, C and D are wrong.