The correct answer is option 2) i.e. Repress.From the first part of the analogy, it becomes clear that the two words are opposite in meaning i.e. 'Explicit' is the antonym of 'Implicit'. Similarly, the antonym of 'Express' will be ''Repress'.The meaning of the words are given below:Explicit: fully revealed or expressed without vagueness, implication, or ambiguity : leaving no question as to meaning or intent.Implicit: involved in the nature or essence of something though not revealed, expressed, or developed.Express: to make known the opinions or feelings of (oneself).Repress: to prevent the natural or normal expression(feelings), activity, or development of.