There is a growing concern among the industry leaders that the New Economy companies are not as adept
at managing their inventories as their old-line counterparts and, consequently, vulnerable to the vagaries of market realities.
"
As" is used to present comparison so the structure should be "
...as...as...", therefore B and C out.
Eliminate A since "As" should be followed by a clause.
"
Their old-line counterparts" implied that it happened in the past so eliminate E.
Left only D hence correct.
A. at managing their inventories as
their old-line counterparts and, consequently, vulnerable
B. at managing their inventories
than their old-line counterparts and, consequently, are vulnerable
C. at managing their inventories
as well as their old-line counterparts and, consequently, are vulnerable
D. at managing their inventories as their old-line counterparts were and, consequently, are vulnerable --- Correct
E. with managing their inventories as their old-line counterparts
are and, consequently, were vulnerable