GMAT prep problem. Need help

[abhi.iitb]

[theCodeToGMAT]

Unlike that of earlier works on slavery, Blassingame's innovative study relies not on the records of White slave owners but on the records of the salves themselves, especially the 70 or so autobiographies and memoirs that have been preserved.

A. that of earlier words on slavery, Blassingame's
INCORRECT; correct idiom is Unlike X,Y where X & Y are comparable
B. that of earlier works on slavery, Blassingame in his
INCORRECT; correct idiom is Unlike X,Y where X & Y are comparable
C. earlier works on slavery, Blassingame in his
INCORRECT; correct idiom is Unlike X,Y where X & Y are comparable
D. earlier works on slavery, Blassingame's
CORRECT; comparable X & Y
E. the earlier works on slavery, Blassingame in his
INCORRECT; correct idiom is Unlike X,Y where X & Y are comparable

[abhi.iitb]

Thank Rahul. I was confused between B and D option. but, now i am clear.