Question

and george, while his intelligence was way above normal, had a little mental handicap radio in his ear. he was required by law to wear it at all times. it was tuned to a government transmitter. every twenty seconds or so, the transmitter would send out some sharp noise to keep people like george from taking unfair advantage of their brains.
—\harrison bergeron,\ kurt vonnegut
what clue in this passage helps show that this short story is science fiction?
the use of advanced technology
a character with high intelligence
laws that are enforced by supernatural beings

Explanation:

Science fiction often features advanced technology. In this passage, the "mental handicap radio" is an example of such technology. A character with high intelligence (common in many genres) and laws enforced by supernatural beings (not indicated here) don't specifically point to science fiction like advanced technology does.

Answer:

the use of advanced technology