A firm has a net profit margin of $1\mathrm{.}24,$ a leverage ratio of $2,$ an asset turnover ratio of $2\mathrm{.}5,$ a current ratio of $1\mathrm{.}5,$ and a return on sales ratio of $4\%.$ The firm's ROE is:

Select one:

a$.4\mathrm{.}2\%$

b$.5\mathrm{.}2\%$

c$.6\mathrm{.}2\%$

d$.7\mathrm{.}2\%$