The volume of a small packing box is "3x^2 + 3x" in^3 smaller than a large packing box with a volume of "5x^2 − 2x + 10" in^3. Find a single expression that represents the size of a small packing box.
A) 2x2 − 2x + 10
B) 2x2 − 5x + 10
C) 8x2 − 5x + 10
D) 8x2 + x + 10