The standard deviation of stock 1 is 10%, and that of stock 2 is 20%, and the correlation between them is +0. You have $10,000 invested in these stocks with $2,500 of the money in stock 1 and $7,500 the money in stock 2, please calculate the portfolio standard deviation (Hint: the weight given to stock 1 is 0.25 and the weight given to stock 2 is 0.75) 15.21% 22.50% 20.50% 34.50%