Which one of the following words is opposite in meaning to 'reveal' (Para-5) as used in the passage?

'Reveal' means to make known or show. Its opposite is 'conceal', meaning to hide. 'Blacken' means to make dark, 'repeal' means to revoke a law, and 'teal' is a color. Only 'conceal' is the proper antonym of 'reveal'.