xYou are considering purchasing a house that costs $$100,000.$ Assuming you have $$20,000$ available for a down payment and plan to borrow the remainder over $15$ years at $5\%$ interest, your monthly mortgage payment will be $\_\_\_\_\_.($Hint $--$ you are paying back the $$80,000$ that you are borrowing today$).$

A$.$ $$588\mathrm{.}19$

B$.$ $$632\mathrm{.}63$

C$.$ $$702\mathrm{.}27$

D$.$ $$646\mathrm{.}29$