Which sentence is an example of a metaphor? the bear was big and brown. the squirrel scurried up the tree. the cat's purr was a soft lullabye. the lion's roar was fierce and scary.

The cat's purr was a soft lullaby

Explanation:

The other answers are just descriptions of the animals aka adjectives, which are facts e.g the bear is big and brown is a factual way on describing a bear while the cat's purr was a soft lullaby is a figure of speech which is not literally applicable. Others could describe it differently, by using metaphors such as cat's purr was a lovely melody but factually and adjectival we could say about the cat that it's purr was nice.

is that the whole question?

explanation:

it refers to the definition of full-contact sports, where the condition is that the sport must have athletes must "purposely collide with each other