Use the Formula $\mathrm{N}=\mathrm{Ie}^{\mathrm{kt}}$ , Where $\mathrm{N}$ Is the Population at Time $\mathrm{t}$

Use the formula $\mathrm{N}=\mathrm{Ie}^{\mathrm{kt}}$ , where $\mathrm{N}$ is the population at time $\mathrm{t}$ , $\mathrm{I}$ is the initial population, and $\mathrm{k}$ is a growth constant equal to the percent of growth (expressed in decimal form) per unit of time. How long will it take for the population of a certain country to double if its annual growth rate is $7.8 \%$ ? Round your answer to the nearest year.

A) $4 \mathrm{yr}$
B) $1 \mathrm{yr}$
C) $9 \mathrm{yr}$
D) $26 \mathrm{yr}$