Bob purchased Amy's engagement ring on January $1,1992$ with a $$10,000$ loan. His loan carries an interest rate of $21\%$ per year

convertible monthly. He pays $$600$ per month starting February $1,1992,$ plus an additional $$1600$ on June $1,1992.$ His last payment will

be a partial payment.

Determine when he will make the last full payment of $$600.$

April $1,1993$

May $1,1993$

June $1,1993$

July $1,1993$

August $1,1993$