Answer:
The correct option is;
1. A physical room that bounces sound off the wall
Step-by-step explanation:
In Engineering, An echo chamber is a room which is used to produce a persistent repetition of a sound after the initial sound is made mainly with the intention of recording purpose
Echo chambers are used in radio programming for sound cave or large room sound effects such that the reverberations are picked up by microphones which provides amplification
Current day echo chambers are achieved by electronic sound effects functions present in modern sound equipment, however, physical echo chambers, such as the famous Capitol Studios echo chambers are still in use.