What makes waves in the ocean?

They ignored the moon because, although small compared with wind, it's tidal effect also adds to waves.

Tom, I think using “sun” as a choice was an acknowledgment of the moon because including it would make two correct answers.

It could be argued that the sun heats up the landmasses, the resulting temperature differences create wind. (Did I get that right?)

And the wind comes from uneven heating by the sun...

Tom, thanks I wondered why the moon wasn't an option

The motion of the waves and tides is an untapped source of free - and clean - power. About time we tapped it.

The sun is also a correct response, as it helps create tides, which is a wave with a period of 12:25 or 24:50.