In a souvenir shop, Jodi purchased 2 small picture frames and 1 large one for $28. Mike bought 3 medium-size frames and 2 large ones for $56. Shelly bought a small, a medium, and a large frame for $30. Write and solve a system of equations to find the price of each size of picture frame.
a.small: 8
medium: 10
large: 12
b.small: 5
medium: 10
large: 15
c.small: 6
medium: 8
large: 16
d.small: 10
medium: 12
large: 15