Chapter 15.6, Problem 3PT

${\displaystyle \underset{E}{\iiint }zdV}$, where E is the wedge-shaped solid shown at the right, equals:

1. a) ${\displaystyle {\int }_0^4{\displaystyle {\int }_0^3{\displaystyle {\int }_0^{6-2x}zdzdxdy}}}$
2. b) ${\displaystyle {\int }_0^4{\displaystyle {\int }_0^3{\displaystyle {\int }_0^{6}zdzdxdy}}}$
3. c) ${\displaystyle {\int }_0^4{\displaystyle {\int }_0^3{\displaystyle {\int }_0^{6-z}zdxdzdy}}}$
4. d) ${\displaystyle {\int }_0^4{\displaystyle {\int }_0^3{\displaystyle {\int }_0^{6-x-y}zdzdxdy}}}$