The correct option is B He tightens the skin by stretching the string around it.
Answer is C.
The top of the tabla drum is covered with a stretched, layered leather membrane held in place by leather braces. The wooden pegs between the braces and the drum adjust the tension in the braces, thus controlling the pitch of the instrument.
Hence, to increase the pitch of the sound produced the player tightens the skin by stretching the string around it.