Concept: The key distinction lies in how transactions are recorded: double entry records both aspects, while single entry records only one aspect.Explanation:Double entry is based on the dual concept, meaning every transaction has a two-fold effect: a debit and a credit.Single entry does not follow the dual concept; it records incomplete or one-sided transactions.Thus, the correct difference is that double entry is based on the dual concept, while single entry is not.Answer: A. double entry is based on the dual concept while single entry is not based on dual concept.