Which of the following is true of a debit and a credit in the T account of a revenue and an expense account? O a. A debit in a revenue account signifies an increase in revenue, and a credit in an expense account signifies an increase in an expense. Ob. A credit in a revenue account signifies an increase in revenue, and a debit in an expense account signifies an increase in an expense. Oc. A credit signifies an increase in both a revenue and an expense account Od. A debit signifies an increase in both a revenue and an expense account