30) According to the mean-variance criterion, which one of the following investments dominates all others? A) E(r)=0.15; Variance =0.20 B) E(r)=0.10; Variance =0.20 C) E(r)=0.10; Variance =0.25 D) E(r)=0.15, Variance =0.25 E) E(r)=0.12; Variance =0.35