A household's monthly utility bill consists of a fixed fee and a usage charge. The fixed fee is 30 dollars, and the usage charge is 0.12 dollars per unit $u$ consumed. Which algebraic expression represents the total monthly bill?

• A. $30+0.12u$
• B. $30-0.12u$
• C. $30u+0.12$
• D. $0.12+30u$

Answer: (A)