Matilda Owns an Office Supply Store

Matilda owns an office supply store.If she decided to expand the size of her store in order to sell more supplies,how would she know if she is experiencing diseconomies of scale?

A) Her total cost of selling supplies decreases.
B) Her average cost of selling supplies increases.
C) Her total cost of selling supplies remains unchanged.
D) Her average cost of selling supplies remains unchanged.
E) Her average cost of selling supplies decreases.