The superposition of mechanical waves can be observed in the movement of

I found your question in a worksheet and since you listed no options if I'm correct, the options were
A. Bumper Cars
B. waves in a ripple tank.
C. electromagnetic radiation
D. an orchestra
Well technically all of the above would be correct since the matter waves are real but have relatively short wavelengths that aren't immediately obvious and what we see is really just the superposition of matter waves, the best answer would be B, waves in a ripple tank.