The sentence that uses the denotation of the word "heart" is "The heart pumps blood in the body." Denotation refers to the literal or primary meaning of a word, so in this case, the word "heart" is being used in its literal sense – the organ that pumps blood in the body. To determine which sentence uses the denotation of a word, you need to consider the actual dictionary definition of the word and its most basic meaning. In this case, the other sentences use the word "heart" metaphorically or figuratively.
