Question: In EVS (Enhanced Voice Services) codec, as per 3GPP standards, at what bitrate and under which background noise condition is comfort noise addition applied?
Option 1: For bitrates above 24 kbps when background noise level >= 10
Option 2: For bitrates of 8.85 kbps and below when background noise level >= 15
Option 3: For all bitrates when background noise level >= 20
Option 4: For bitrates between 12.65 kbps and 24 kbps when background noise level >= 5
Explanation: This is correct because, according to the specified conditions for comfort noise addition in EVS codec, the process is triggered specifically for lower bitrates (8.85 kbps and below) in scenarios where the background noise level is particularly high (>= 15), aiming to maintain perceptual quality under such conditions.