second picture:
Wave B consists of 3 waves a,b,c. Why not just 1,2,3? Because numbers are used to label impulses only. impulses have 5 waves always. Numbers always display corrections.
Some corrections partly consist of small impulses. For example a zigzag is counted 5-3-5. So wave A and C consist of impulses 1,2,3,4,5 and wave B is corrective a,b,c. On a higher timeframe this is still only a corrective structure signalling trend continuation.