They have had their debt written _____ by their creditors?
Answer Details
The option that best completes the sentence is "off."
In this sentence, "written off" means that the creditors have cancelled or forgiven the debt, usually because it is unlikely that the debtor will be able to repay it. So, "off" is the correct option.
The other options are not suitable because they have different meanings. "Written down" means to reduce the value of an asset, usually in accounting. "Written on" does not have a commonly recognized meaning in this context. "Written up" means to increase the value of an asset, usually in accounting. None of these options capture the meaning of "written off" in this sentence.