In which of the following cases can a lender sue for foreclosure?

A lender can sue for foreclosure primarily in the event that the borrower defaults on their mortgage payments. When a borrower fails to make the required payments as outlined in the mortgage agreement, it constitutes a breach of contract. This breach allows the lender to initiate foreclosure proceedings to reclaim the property. Foreclosure is a legal process that enables the lender to sell the property in order to recover the outstanding debt.

The other situations mentioned do not automatically give the lender grounds for foreclosure. For instance, if a borrower sells the property, they typically must pay off the mortgage, and it does not affect the lender's right unless the mortgage terms are violated. If a borrower simply moves out of state or refinances, these actions do not constitute default; they may still be meeting their mortgage obligations. Therefore, defaulting on payments is the critical factor that grants the lender the ability to pursue foreclosure.