The Iterated Integral $\int_{0}^{\frac{\pi}{4}} \int_{0}^{2 r} \int_{0}^{\cos \theta} r \sec ^{3}(\theta) d z d r d \theta$

Multiple Choice

The iterated integral $\int_{0}^{\frac{\pi}{4}} \int_{0}^{2 r} \int_{0}^{\cos \theta} r \sec ^{3}(\theta) d z d r d \theta$
is

A) $\frac { 10 } { 3 }$
B) $\frac { 8 } { 3 }$
C) $\frac { 5 } { 2 }$
D) $\frac { 7 } { 2 }$
E) $\frac { 5 } { 3 }$