This workout is in two phases.
Phase 1 (3 weeks), where you do 3 workouts per week (Mon-Wed-Fri) alternating between workouts A and B, with optional cardio/abs days in between.
Phase 2 (4 weeks), where you do 3 workouts per week, using workout A on Mondays, workout B on Wednesdays and Workout C on Fridays, with optional cardio/abs days in between.