For each statement, express the null hypothesis H_0 and alternative hypothesis H_1 in symbolic form. 1. IQ scores of statistics students have a standard deviation at most 15. A. H_0 :μ<15,H_1 :μ≥15 B. H_0 :σ≥15,H_1 :σ<15 C. H_0 :μ≤15,H_1 :μ>15 D. H_0 :σ≤15,H_1 :σ>15