A bank's estimate of next year profit $($as a percentage of assets$)$ is a normal distribution with mean and standard deviation of $1\%$ and $2\%,$ respectively. How much equity $($as a percentage of assets$)$ does the company need so that the probability of a negative equity at the end of the year is less than $0\mathrm{.}1\%?$

a$.4\mathrm{.}18\%$

b$.7\mathrm{.}18\%$

c$.1\mathrm{.}09\%$

d$.5\mathrm{.}18\%$