The correlation coefficient between a stock and the market portfolio is $0\mathrm{.}4.$ The standard deviation of return of the stock is $15$ percent and that of the market portfolio is $10$ percent. Calculate the beta of the stock.

Multiple Choice

$0\mathrm{.}8$

$0\mathrm{.}7$

$0\mathrm{.}6$

$0\mathrm{.}3$