For three of the four, you have named the medium ... rope, slinky, and tuning fork. In each case, there would be no wave without it.
The radio wave , as well as all other electromagnetic waves, can travel through material media, but don't need one in order to propagate.
The answer is radio wave, waves on the electromagnetic spectrum don't need a medium
The type of wave that does not require a medium to travel through is the radio wave (option B). Unlike mechanical waves, radio waves are electromagnetic waves and can propagate through a vacuum. This unique property enables them to travel without any physical medium.
;