Questions: What are the configurations for the two chirality centers? A. a=R, b=R B. a=S, b=S C. a=R, b=S D. a=S, b=R

What are the configurations for the two chirality centers?

Assign priorities to the groups attached to chiral center a.

The priorities for chiral center a are:

1. Cl
2. COOH
3. CH₂CH₃
4. H

Determine the configuration of chiral center a.

Following the path from 1 to 2 to 3, the direction is clockwise. Since the lowest priority group (H) is pointing away from the viewer, the configuration is R.

Assign priorities to the groups attached to chiral center b.

The priorities for chiral center b are:

1. Cl
2. COOH
3. CH₂CH₃
4. H

Determine the configuration of chiral center b.

Following the path from 1 to 2 to 3, the direction is counterclockwise. Since the lowest priority group (H) is pointing away from the viewer, the configuration is S.

\( \boxed{\text{C. } a=R, b=S} \)

\( \boxed{\text{C. } a=R, b=S} \)