I'd definitely consider it a third option, "garbage collection" to me strongly implies the existence of a "garbage collecter" à la tracing collectors. Reference

I'd definitely consider it a third option, "garbage collection" to me strongly implies the existence of a "garbage collecter" à la tracing collectors. Reference counting injects reference checks/increments and destructors into the program itself, which means you don't have a separate routine running independently (and nondeterministically) of the main program. The phrase "garbage collection" has also come to be somewhat associated with tracing's specific characteristics (IMO). Manual memory management is performant and deterministic, but unsafe. Tracing garbage collection is performant and safe, but nondeterministic. Reference counting is deterministic and safe, but not as performant. If you throw Rust into the mix as a fourth option I suppose you could add a "flexible" characteristic.