In this question, a related pair of words is followed by four pairs of words. Select the pair that best expresses a relationship similar to that expressed in the original pair.
'LIQUEFY : PETRIFY'

The pair of words that most closely reflects the same relationship as "LIQUEFY : PETRIFY" is "MELT : FREEZE." Each pair illustrates opposing processes related to state changes in matter: liquefy refers to transforming into a liquid, whereas petrify signifies becoming solid, similar to how melt contrasts with freeze.

Let's analyze other options:

Option-A: Blend : Separate: While these words are related to different actions, they are not antonyms like the original pair. Blending involves combining, while separating is the opposite.

Option-B: Cash : Invest: This pair represents a financial transaction, not a change in state of matter. Cashing out is converting an asset to cash, while investing is putting money into something to potentially grow it.

Option-D: Soften : Frighten: These words are not related in terms of state change. Soften refers to a change in texture, while frighten is an emotional response.

So, option C is the correct answer.