Under 14 CFR § 107.39, over which of the following may a remote pilot operate a small unmanned aircraft without meeting one of the operational categories in part 107 subpart D?

Why: 14 CFR § 107.39 bars operating over a human being unless that person is directly participating in the operation, is under safe cover, or the operation meets one of the four subpart D categories. AC 107-2A § 8.3, p. 8-1, defines direct participants as the remote PIC, a person manipulating the controls, a visual observer, or necessary crewmembers.

• A passerby on a sidewalk is not "directly participating" under AC 107-2A § 8.3's definition; flying over them requires either safe cover or meeting a subpart D category, not just incidental nearby presence.
• A spectator is likewise not a direct participant; operating over an uninvolved onlooker still requires meeting one of the Category 1–4 requirements under subpart D.