You can climb over there, and not hurt anything. b) there was no use in arguing with a person like this. c) if you were to hit it you would knock the boat's brains out. d) there is plenty of water close up to it, but mighty little on top of it.

c.If you were to hit it you would knock the boat's brains out.

A hyperbole is an effective device of figurative language that is used for emphasis by making a connection between two seemingly unrelated things.  If taken literally, a hyperbole would make no sense.  For instance, boats do not have brains; therefore, if taken literally, that makes no sense.  However, it is basically understood that for something’s brains to be knocked out, it would have to be quite a powerful hit.  Thus, to emphasize/highlight the power of a potential hit to the boat a hyperbole is an effective device here in saying that if the boat were hit, its brains would be knocked out.

which one is underlined?