What is the most likely meaning of the word redaction based on its Latin affix

The word redact comes from the Latin word redactus. (form of redigō)

Redigō = red - + - agō.

Red is just an alternate form of re, which means "again"

Agō means to do, act, make, move, discuss, etc.

Together, the word redigō means to collect, reduce, or bring back.

Thus, the answer is B.

*In Modern English, redact is usually used to refer to blacking something out on the release of a document.