What button is used to accept signal from both the large and small insert return?

The button used to accept a signal from both the large and small insert return is labeled as INS. This designation is commonly associated with insert functions in various audio and signal processing equipment, where selecting the appropriate return channels is essential for proper signal routing. By utilizing the INS button, users can effectively manage input from both large and small returns, ensuring that the desired audio is processed as intended.

The other options typically serve different functions that do not directly pertain to accepting signals from multiple insert returns. Understanding the specific use case of the INS button reinforces its importance in managing insert effects in audio production environments.