What Does It Mean for a Loan to Be in Default

What does it mean for a loan to be in default?

A) when the borrower of the a loan fails to repay on schedule according to a loan contract, without the agreement of the lender
B) when the borrower of a loan fails to repay on schedule according to a loan contract, with the agreement of the lender
C) when the lender of a loan fails to supply the full amount of a loan to the borrower
D) when the lender of a loan supplies the full amount of a loan to a borrower without any promise of being repaid
E) when the lender of a loan fails to offer the promised sum