Amirror faces a cliff located some distance away. mounted on the cliff is a second mirror, directly opposite the first mirror and facing toward it. a gun is fired very close to the first mirror. the speed of sound is 336 m/s. how many times does the flash of the gunshot travel the round-trip distance between the mirrors before the echo of the gunshot is heard?

The speed of light is  299,792,468 m/s .

The speed of sound is  336 m/s .

The speed of light is (299,792,458 / 336) = 892,239 times the speed of sound.

By the time the sound has reached the side of the cliff and echoed
back to the shooter's position, the flash of the shot has made the same
round trip  892,239 times.

(Maybe possibly perhaps only 892,238 times, since the speed of light
is slightly slightly slightly slightly less in air.)

The answer should be a.