The correct answers are: Cash received after the period-end; Receivable payment patterns; Delivery notes signed by the customer; Contractual arrangements with the customer.

Cash received after the period-end proves that the debt has been recovered. Trade receivable payment patterns may indicate a problem with payments (if debts are building up).

Delivery notes signed by the customer indicate that the customer is obliged to pay or to return the goods and contracts with the customer also indicate an obligation to pay.

The company's credit limit policy does not provide evidence as to whether a customer will pay.