II.Solving the problem \text { A. If } \mathrm{f} \text { is continuous show that } \int_{0}^{\gamma} \int_{0}^{Y} \int_{0} f(t) d t d z d y=\frac{1}{2} \int_{0}^{3}(x-t)^{2} f(t) d t

B. Change the order of integration C. Change the limits \text { D. } \mathrm{E}=\{(t, y, z) \mid 0 \leq t \leq z, 0 \leq z \leq y, 0 \leq y \leq x\} E. x=y = z=t= 0