Two boys are communicating with each other by stretching a string passing through a hole punched in the bottom of each of two tin cans. The physical principle employed is that sound travels

A.

mainly through air

B.

fainter in stretched string

C.

faster through gases than in solids and liquids

D.

with greater ease through a string than in air

E.

none of the above is correct

Correct answer is D

No explanation has been provided for this answer.