Question

A ________ editor was the dominant way film was edited up until the early '90s.

dual rectifier
flatbed
digital
film harmonizer

Answer 1

Flatbeds were prominently used up until the mid 90's and were replaced by non-linear software.

Answer 2

Answer: flatbed.

Explanation:

In the early days, before digital video were able  to offer the same resolution as the physical 35 mm film, film editing was done with a razor and tape, joining the parts of the film, once removed the undesired footage.

By mid-90's, all editing process became digital, done in the NLE memory,  like in the legendary Avid Composer, .