The cost of packing a box of chocolates is given by 1/4x^2, where x is the number of chocolates (a box can never have fewer than 3 chocolates). If the weight of a box of chocolates is given by x + 2, what is the cost of packaging per weight unit?
A.1/4x-1/2+1/x+2

B.1/4x^2-1/2x+1

C.1/4x^2-1/2+1

D.1/4x-1/2x-1/x+2