$21\mathrm{.}1$ Compute the future value of the following deposits made today:

a$.$ $$10,000$ at $6\mathrm{.}75\%$ compounding annually for $10$ years

b$.$ $$10,000$ at $6\mathrm{.}75\%$ compounding quarterly for $10$ years

c$.$ $$10,000$ at $6\mathrm{.}75\%$ compounding monthly for $10$ years