Apprehend : emancipate ::

a. deflect : reflect

b. imply : know

c. mandate : authorize

d. reprehend : criticize

e. conceal : manifest

Since the words apprehend:emancipate are basically antonyms, they mean completely the opposite, (apprehend means to arrest, limit someone's freedom, whereas to emancipate means to liberate) we need to find a pair of words which also have opposite meanings.

The correct answer is E) conceal:manifest. Conceal means to hide, and manifest to show, so you can see they are opposite.