Can you explain the formula?

Portfolio P consists of two stocks: 50% is invested in Stock A and 50% is invested in Stock B. Stock A has a standard deviation of 25% and a beta of 1.2, and Stock B has a standard deviation of 35% and a beta of 0.80. The correlation between these stocks is 0.4. What is the standard deviation of Portfolio P? A. less than 30% B. equal to 30% C. impossible to compute D. more than 30% Submit