In the context of the standard electroweak model, we emphasize that B_d→D _CP ⁰ K_S (D _CP ⁰ denotes aCP eigenstate of D⁰ or [`(D)]\overline D <sup>0</sup>) can compete with B<sub>d</sub>→→π<sup>+</sup>π<sup>−</sup> in studyingCP violation and probing the Cabibbo-Kobayashi-Maskawa unitarity triangle. We discuss the measurables of direct and indirectCP asymmetries in B <sub>d</sub> <sup>0</sup> vs. [`(B)]\overline B _d ⁰ →D _CP ⁰ K_S in the circumstance of an asymmetric B-meson factory running on the γ(4S) resonance, and show that both the weak and strong phases are experimentally determinable even in the presence of unknown final-state interactions.