Which statement is correct?

A$.$ Workers in nonprofits tend to be the easiest to poach by firms paying a little more money.

B$.$ For$-$profits rely more on intrinsic motivation than on performance$-$related pay.

C$.$ In large, for$-$profit companies it is particularly hard to quantify and measure the objective for the company and an individual worker$$s contribution to that objective.

D$.$ External constraints apply to nonprofits, the public sector, and small businesses.