Allthough similar to the what instrument do you play, this one is someone easier to underaand and gives a clear result to the most popular instrument.
I am sincerley sorry for not adding the other hundreds of insturments as it would take quite some time so i added some of the main ones.
I've voted for Bass guitar, as it's my main instrument, by quite some way. To be more specific, fretless bass guitar. I do also play 'regular' guitar, and keyboards.