Which one of the following is NOT a trade-off decision that must be made in the development of the project plan

A) Whether to use skilled or unskilled laborers.
B) The amount of profit vendors should make versus the profit other vendors have received in the past.
C) Manufacturing in-house or sub-contracting out the work.
D) The important of cost versus quality.

材料的利用率是指余料的总面积与工件的总面积之比。（）