OG Verbal Review - SC - #16

[Gmat2Go]

Declining values for farm equipment and land, the collateral against which farmers borrow to get through the harvest season, isgoing to force many lenders to tighten or deny credit this spring.
(A) the collateral against which farmers borrow to get through the harvest season, is
(B) which farmers use as collateral to borrow against to get through the harvest season, is
(C) the collateral which is borrowed against by farmers to get through the harvest season, is
(D) which farmers use as collateral to borrow against to get through the harvest season, are
(E) the collateral against which farmers borrow to get through the harvest season, are

OA is E. I was able to eliminate A/B/C due to is/are verbal agreement issues. But, I can't figure out why OA is E.
Should D be better because it uses "which" , to clearly refer to farm equipment and land. Please explain

[Guest]

Sorry the reference is Verbal Review not OG. Thanks

[StaceyKoprince]

Choosing between D and E is certainly tricky here. D is redundant. To "use [something] as collateral" is "to borrow against" that thing. You can say one or the other in a sentence (and E goes with the "borrow against" version) but, if you use both, you're saying the same thing twice! Most people miss that on this one - tough one.