Solve the Problem $\mathrm { A } = \mathrm { Ie } \mathrm { kt } , \mathrm { A }$

Multiple Choice

Solve the problem.
-In the formula $\mathrm { A } = \mathrm { Ie } \mathrm { kt } , \mathrm { A }$ is the amount of radioactive material remaining from an initial amount I at a given time $t$ and $k$ is a negative constant determined by the nature of the material. A certain radioactive isotope decays at a rate of $0.175 \%$ annually. Determine the half-life of this isotope, to the nearest year.

A) $286 \mathrm { yr }$
B) $172 \mathrm { yr }$
C) $396 \mathrm { yr }$
D) $4 \mathrm { yr }$