For the office building in the preceding table, compute the following for 2007:
a. Monthly natural gas consumption based on Btu/ft ${ }^2$ of floor area.
b. Annual natural gas consumption based on $\mathrm{Btu} / \mathrm{ft}^2$ of floor area.
c. Monthly natural gas consumption normalized for weather conditions (degree-days), based on $\mathrm{Btu} / \mathrm{ft}^2$. ( ${ }^{\circ} \mathrm{F} \cdot \mathrm{day}$ ).
d. Annual natural gas consumption normalized for weather conditions (degree-days), based on $\mathrm{Btu} / \mathrm{ft}^2$. ( ${ }^{\circ} \mathrm{F} \cdot$ day).