this question is testing the use of past perfect tense:
(A) He was more busy and stressed after he
had moved to Chicago compared to Oklahoma, financier Mark Robertson nevertheless
(B) Being more busy and stressed after he
had moved to Chicago as compared to Oklahoma, financier Mark Robertson nevertheless
(C) Financier Mark Robertson was more busy and stressed after he moved to Chicago than
he had been back in Oklahoma, nevertheless he
(D) Financier Mark Robertson was more busy and stressed after moving to Chicago when compared to Oklahoma, nevertheless he
(E)
He had been more busy and stressed after moving to Chicago than in Oklahoma, financier Mark Robertson nevertheless
lets look at the sequence of events:
1) 1st busy and stressed in Oklahama
2) moved to chicago
3) busy and stressed in chicago
therefore use the past perfect tense for the 1st event
only option C uses the correct verb tense order!