A device based on multiple reflection used for sending amplified sound in a particular direction is:
(A) Bulb horn
(B) Megaphone
(C) Ear trumpet
(D) All

Hint: Multiple reflections means that the sound is reflected more than once so we will have to find out from the given options the device used to amplify the sound and direct it in a given direction.

Complete step by step solution:
Megaphone is based on multiple reflections of sound. It is shaped like a horn and amplified sound can be sent in a particular direction.
Multiple reflections means the sound is reflected more than once and the repeated reflection that results in this persistence of sound is called reverberation.
Megaphone works on the principle of multiple reflection of sound. It is designed to prevent the spreading of sound produced in all directions but to make the sound propagate in a particular direction.
Option (B) is correct.

Note:
Megaphone is also known as speaking-trumpet, bullhorn, blow- horn or loud-hailer.
A megaphone is a portable or hand-held, cone-shaped acoustic horn. It amplifies the person’s voice or other sounds and directs it to a given direction.
In it, the sound is introduced into the narrow end of the megaphone and sound waves radiate out the wide end.
Electric megaphones consist of a microphone to convert sound waves into electrical audio signal, an amplifier powered by a battery to increase the power of audio signal, an amplifier powered by a battery to increase the power of audio signal, and loudspeakers to convert audio signal to sound waves again.