Martina's grandparents paid for the first $3$ years of her college costs. As a senior, she was approved for a federal unsubsidized loan in the amount of $$9,300$ at a $4\mathrm{.}29\%$ interest rate for $10$ years.

a$.$ If she chooses to make interest$-$only payments until the monthly loan payments are due, for how long will she be making interest$-$only payments? Express as a decimal $($in years$).$

b$.$ What would be the total amount of her interest$-$only payments?

c$.$ If she begins her loan repayment with no interest capitalization since she already paid the interest when she was in school and during the $6-$month grace period, how much will she have paid in interest for this loan by the end of the $10-$year loan period?