Solve
-The Function $\mathrm{A}=\mathrm{A}_{0} \mathrm{e}^{-0.0077 \mathrm{x}}$ Models the Amount in Pounds of a Particular Radioactive Material

Multiple Choice

Solve.
-The function $\mathrm{A}=\mathrm{A}_{0} \mathrm{e}^{-0.0077 \mathrm{x}}$ models the amount in pounds of a particular radioactive material stored in a concrete vault, where $\mathrm{x}$ is the number of years since the material was put into the vault. If 900 pounds of the material are initially put into the vault, how many pounds will be left after 80 years?

A) $506 \mathrm{lb}$
B) $413 \mathrm{lb}$
C) $486 \mathrm{lb}$
D) $400 \mathrm{lb}$