Which of the following statements is not true regarding subsidiary ledgers?

1. Subsidiary ledgers can be established in connection with any general ledger account where the availability of component information is helpful.

2. Accounting systems can be programmed so that each entry into the general ledger T-account requires an immediate parallel increase or decrease to the appropriate individual account.

3. They are a group of individual accounts whose sum agrees with, and therefore explains, a general ledger account balance.

4. Keeping subsidiary ledgers, even in computer systems, is an arduous task which is often fraught with errors.