Playing the involves scraping two metal disks together.

Question: Playing the  involves scraping two metal disks together.

Crash Cymbals

Explanation:

On OW the options are

I looked up a picture of each one.

Obviously a triangle can't be the answer. A triangle is, well, a triangle that makes a dinging noise. (You know what I mean)

A gong would be my second option is Crash Cymbals isn't correct although it only uses, ONE disk and a mallet.

An Organ doesn't involve any disks. Rather keys and tubes you could say.

And lastly, Crash Cymbals, (if you look up a picture) DOES have two disks being hit against each other with drumsticks on your usual drum-set.

SO, the first answer I'd go with is Crash Cymbals.

i think this is true