Multiple choice Bit stuffing refers to inserting a '0' in user data stream to differentiate it with a flag inserting a '0' in flag stream to avoid ambiguity appending a nibble to data stream appending a nibble to flag stream Reveal answer Fill a bubble to check yourself A Correct answer Explanation Bit stuffing is used in protocols like HDLC to ensure that a specific flag sequence (e.g., 01111110) does not appear within the actual data payload, preventing the receiver from misinterpreting the end of a frame.