Answer :
Both Technician A and Technician B are correct: the EVAP monitor can detect evaporative system leaks and differentiate between large and small leaks, setting the appropriate DTCs. Therefore, option c. both a and b is the correct answer.
The subject of the question concerns the EVAP (Evaporative Emission Control System) monitor, which is part of a vehicle's emissions system. Specifically, the question is regarding the monitor's capabilities in detecting evaporative system leaks and differentiating between the sizes of those leaks.