Concept:The ledger is a book of accounts that follows the double-entry system of recording transactions.
Explanation:A transaction always affects at least two accounts.
One account is debited and another account is credited.
The total value of every debit entry must equal the total value of the corresponding credit entry.
This is known as the double-entry principle.
When transactions are posted from source documents into the ledger, the posting is done in line with this principle.
That is why each transaction is entered on both the debit side and the credit side of the relevant accounts.
Source documents serve as evidence, but they do not determine the method of ledger posting.
It is the double-entry principle that guides how the ledger entries are made.
Answer:C. Double Entry Principle