设 $X_{1}, X_{2}, X_{3}$ 是随机变量，且 $X_{1} \sim N(0, 1), X_{2} \sim N(0, 2^{2}), X_{3} \sim N(5, 3^{2}), p_{i} = P\{-2 \leqslant X_{i} \leqslant 2\}$ （ $i = 1, 2, 3$ ），则（） $(\mathrm{A})p_{1} > p_{2} > p_{3}$ (B) $p_2 > p_1 > p_3$ $(\mathrm{C})p_{3} > p_{1} > p_{2}$ $(\mathrm{D})p_{1} > p_{3} > p_{2}$