The correct answer is $\boxed{\text{A. R, R}}$.
The configuration of a chiral center is designated as R or S, depending on the direction of rotation of a Cahn-Ingold-Prelog priority sequence around the chiral center. The priority sequence is determined by the atomic number of the atom bonded to the chiral center, followed by the atomic number of the atom bonded to that atom, and so on. If the rotation is clockwise, the configuration is R. If the rotation is counterclockwise, the configuration is S.
In the reaction shown, the reactant has two chiral centers. The configuration of the first chiral center is R, and the configuration of the second chiral center is R. The product also has two chiral centers. The configuration of the first chiral center is R, and the configuration
74.6 75.5c-23.5 6.3-42 24.9-48.3 48.6-11.4 42.9-11.4 132.3-11.4 132.3s0 89.4 11.4 132.3c6.3 23.7 24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube