27. What configurations are found in the product(s) of the reaction shown below?  
(A) 1R, 2R only
(B) 1S, 2S only
(C) 1R, 2S only
(D) An equal mixture of 1R, 2R and 1S, 2S
(E) An equal mixture of 1R, 2R and 1R, 2S