I have found the following question on the Chemistry GRE test guide.
My answer to this was (B) which 2R, 3S; however, the answer key show that the right answer is: (D) 2S, 3S
I have reviewed my answer several time. I just don't buy it, I am sure the right answer is B and find no reason why it would be D
The way I have ranked the priority on the left side chiral carbon is: C-OH is number 2, and C=O is number 3, and OH is 1, and H is the fourth. Because C=O is attached to and O and H (less priority than C), but C-OH attached to OH and another CH2.
Any idea if I am right or they are right?