When (S)-2-Bromobutane Undergoes an S_N2 Reaction with CH₃O^-, the Product

When (S) -2-bromobutane undergoes an S_N2 reaction with CH₃O^-, the product is the compound shown below. What is/are the configuration(s) of the product(s) obtained from this reaction?

A) S only
B) R only
C) a mixture of enantiomers with more R than S
D) a mixture of enantiomers with more S than R
E) equal mixture of R and S