What Is the IUPAC Name for the Following Compound $\alpha$ $\beta$

What is the IUPAC name for the following compound?

A) 2,3-dimethylbutanenitrile
B) $\alpha$ , $\beta$ -dimethylbutyrnitrile
C) $\beta$ , $\gamma$ -dimethylbutyrnitrile
D) 3,4-dimethylbutanenitrile
E) 3,4-dimethylpentanenitrile