Penny owes Mandla R $20000$ in respect of several debts. Penny pays Mandla an amount of R$10000$ but does not stipulate which debt$/$s he is actually paying.

Which ONE of the following principles will apply in this case?

Capital is paid before interest.

Onerous debts do not have preference over non$-$onerous debts.

Old debts do not have preference over new debts.

Due debts are paid before debts which have not yet fallen due.