Erosion can best be explained as the:

A. loss of current sales due to a new project being implemented.

B. loss of revenue due to employee theft.

C. additional income generated from the sales of a newly added product.

D. loss of revenue due to customer theft.

A. loss of current sales due to a new project being implemented.

Explanation:

In business, erosion takes place when a new product or project competes with another product or project from the came company. This "internal" competition reduces the revenues and benefits from existing products or projects. It is basically a form of business cannibalization, where the left arm takes away from the right arm. E. g. newer smartphone models decrease the sales revenue from existing (older) models.