Hello, Im stuck on this question. I know the answer is B $8,477.47 but,can some please help explain how I would find the answer? Thank you

Martha is going to receive $6,000 in two years from Tom. She will receive an additional $4,000 in three years from Tom. She earns 7.15% per year compounded annually on her investments. How much is this money from Tom worth to Martha today?

A)	$7,893.46
B)	$8,477.47
C)	$8,891.74
D)	$9,225.97
E)	$9,251.50