The first line focuses on leadership by example. The logical continuation is B, which discusses a specific managerial duty — clear allocation of work — connecting to the theme of direct managerial involvement.
After assigning work, D follows naturally as it emphasises the personal discipline and moral standards leaders should maintain, aligning with the idea of “leading by example.”
Next, A elaborates on another aspect of leadership — continuous skill upgrading to effectively guide subordinates, which is necessary after moral example is set.
Finally, C warns against excessive distancing (“wall-building”), stressing visible leadership presence, which rounds off the sequence before sentence 6 elaborates on structured managerial tasks.
Thus, the coherent order is BDAC.