NADH is produced in which of the following reactions?

A) Malate $\rightarrow$ Fumarate
B) Succinate $\rightarrow$ Fumarate
C) $\alpha$ -Ketoglutarate $\rightarrow$ Succinyl-CoA
D) Succinyl-CoA $\rightarrow$ Fumarate
E) Oxaloacetate $\rightarrow$ Citrate