How Many of These Are Internal Controls Relating to Accounts

Multiple Choice

How many of these are internal controls relating to accounts receivable?
Sending monthly statements of account to customers.
Reviewing slow paying accounts.
Regular reconciliation of the debtors control account and the subsidiary ledger.
Restricting access to the debtor's records.
Allowing debtors discount for early settlement.

A) 2
B) 3
C) 4
D) 5