The correct answer is $\boxed{\text{C. 2(S), 3(S)}}$.
To assign the absolute configuration of a chiral center, we use the Cahn-Ingold-Prelog (CIP) system. The CIP system assigns priorities to the four groups attached to the chiral center, with the highest priority group being assigned 1, the second highest priority group being assigned 2, and so on. The groups are then oriented so that the lowest priority group is pointing away from the viewer. The configuration is then assigned as R (rectus) if the rotation from group 1 to group 2 to group 3 is clockwise, and S (sinister) if the rotation is counterclockwise.
In the molecule shown, the four groups attached to the chiral center at carbon 2 are the hydroxyl group (highest priority), the isopropyl group (second highest priority), the methyl group (third highest priority), and the hydrogen atom (lowest priority). Orienting the groups so that the lowest priority group (hydrogen atom) is pointing away from the viewer, we see that the rotation from group 1 to group 2 to group 3 is counterclockwise. Therefore, the absolute configuration of the chiral center at carbon 2 is S.
The four groups attached to the chiral center at carbon 3 are the isopropyl group (highest priority), the methyl group (second highest priority), the hydroxyl group (third highest priority), and the hydrogen atom (lowest priority). Orienting the groups so that the lowest priority group (hydrogen atom) is pointing away from the viewer, we see that the rotation from group 1 to group 2 to group 3 is clockwise. Therefore, the absolute configuration of the chiral center at carbon 3 is R.
Therefore, the absolute configurations of the two chiral centers in the molecule are 2(S) and 3(R).