Martha and Peter, a married couple filing a joint return, have the following sources of income: Salaries $35,000 Interest income 4,000 Dividends income 3,000 Social security benefits 9,000 Tax-exempt interest 7,000 Both are over 65 years of age. The amount of their AGI should be: A. $49,650 B. $53,500 C. $49,000 D. $4,500