When Jessica had $4$ years left in college, she took out a student $($one$-$time$)$ loan for $$15,970.$ The loan has an annual interest rate of $3\mathrm{.}9\%.$ Jessica graduated $4$ years after acquiring the loan and began repaying the loan immediately upon graduation. According to the terms of the loan, Jessica will make monthly payments for $10$ years after graduation.

a$.$ How much interest will accumulate while she is in school?

B$.$ If jessica does not pay off the intrest that accumulates while she is in school, find her monthly payment.