Money is invested at two rates of interest. One rate is 6%, and the other is 4%. If there is $1300 more invested at 6% than at 4%, find the amount invested at each rate if the total annual interest received is $470. Let x = amount invested at 6%, and y = amount invested at 4%. Then the system that models the problem is x = y + $1300, 0.06x + 0.04y = $470

a. x = $1,300, y = $0
b. x = $650, y = $0
c. x = $1,950, y = $650
d. x = $2,600, y = $1,300