Spanning three generations, the corporate chieftain commenced his career in an obscure internship as a systems processor and culminated in the most prestigious award that the industry associations could bestow.

A - corporate chieftain commenced his career in an obscure internship as
B - corporate chieftain's career commenced in an obscure internship as
C - corporate chieftain had commenced his career with the obscure internship of being
D - corporate chieftain commenced his career with the obscure internship of being
E - career of the corporate chieftain has commenced with an obscure internship of

Source : Grockit

OA : B