How do i solve using a financial calculator?

$11.$ You are thinking of buying a small condominium for $$500,000,$ with a $20$ percent cash down payment. remaining $$400,000$ will be paid monthly over $15$ years or a $180-$ month period with a nominal $9\%$ rate interest on the unpaid balance. What equal monthly payment is required to retire the principal and interest the loan? The loan payment should be computed as a regular annuity.

A$.$ $$4,135$

B$.$ $$4,060$

C$.$ $$3,800$

D$.$ $$3,290$

$12.$ Which of the following statements is most correct?

A$.$ For a company that has debt in its capital structure, the firm's ROE must exceed its ROA.