When an allowance already exists, but is subsequently increased insize, what is the journal entry to record this transaction?

A、Debit
Irrecoverable debts expenseCredit
Trade receivable;
B、Debit
Irrecoverable debts expenseCredit
Allowance for receivable;
C、Debit
Allowance for receivableCredit
Irrecoverable debts expense;
D、Debit
Trade receivableCredit
Irrecoverable debts expense