8. Natasha is going to take out an unsubsidized student loan of $13,500 at a 4.2% APR, compounded monthly, to pay for her last 2 semesters of college. She will begin paying off the loan in 9 months with monthly payments lasting for 12 years, and she's wondering what her monthly payment will be. She's also wondering what her monthly payment would have been if her student loan had been subsidized instead of unsubsidized. Help Natasha figure it out. (5 points: Part 1 - 1 point; Part II - 1 point; Part III - 1 point; Part IV - 1 point; Part V - 1 point) Part I: What is the periodic interest rate of the student loan that Natasha is going to take out?