On January $1,2023,$ Entity C sold merchandise to Entity $D$ for $$4,000,$ terms $\frac{2}{10},$ net $30.$ The merchandise cost Entity $C$$$2,000.$ Both companies use

a perpetual inventory system. Entity $D$ paid Entity $C$ on January $20.$ What amount did Entity D pay to Entity $C?$

$$1,960$

$$4,000$

$$3,920$

$$4,160$