请教一道题

Declning values for farm equipment and land,the collateral against which farmers borrow to get through the harvest seaon,is going to force many lenders to tighten or deny credits this spring.

()the collateral against which farmers borrow to get through the harvest seaon,is

()which farmers use as collateral to borrow against to get through the harvest season,is

()the collateral which is borrowed against by farmers to get through the harvest season,is

()which farmers use as collateral to borrow against to get through the harvest season,are

()the collateral against which farmwe borrow to get through the harvest seaon,are

有点不明白against放在这里什么意思。