Answer:
C. Informal resistance
Explanation:
The kinds of resistance that are difficult to track in the historical record are "informal resistance."
This is because informal resistance is most of the time not coordinated by any recognized groups or leaders. As such, it is difficult to establish and document except in cases where there is widespread violence.
Informal resistance can be in form of civil disobedience but with no active leader or actual plans to the resistance movement.
