Langford Insurance Agency borrowed $$20000$ at $14\mathrm{.}25\%$ simple interest from First Bank to purchase some office furniture. First Bank requires monthly interest payments and the full $$20000$ at the end of $9$ years. In order to meet this obligation, Langford Insurance Agency plans to make monthly deposits to a sinking fund earning $8\mathrm{.}5\%$ compounded monthly. Round up any part of a cent.

a$.$ State Langford Insurance Agency's total monthly obligation

b$.$ State the balance in the sinking fund just after $29$ deposits.

c$.$ Set up a sinking fund schedule on your own paper. Then, state the following:

The amount of interest earned the second month. $

The balance at the beginning of the fourth month. $