When should a [BLANK_AUDIO] tag be used? (Choose all that apply.) (Select all that apply)

1. ONLY when the clip has no audio
2. When there is a 2 second gap where no speaker is speaking
3. When the entire clip is silent, or is filled with static
4. When there is 2 seconds of non plot-relevant audio like typing, writing on board, or incoherent background noise