Solve the Problem $\mathrm { A } = \mathrm { A } _ { 0 } \mathrm { e } ^ { - 0.0099 \mathrm { x } }$

Multiple Choice

Solve the problem.
-The function $\mathrm { A } = \mathrm { A } _ { 0 } \mathrm { e } ^ { - 0.0099 \mathrm { x } }$ models the amount in pounds of a particular radioactive material stored in a concrete vault, where $x$ is the number of years since the material was put into the vault. If 400 pounds of the material are initially put into the vault, how many pounds will be left after 40 years?

A) 269 pounds
B) 119 pounds
C) 114 pounds
D) 350 pounds