Question 4. (Total 20 points) The following data are supplied for the common stocks of Nikola Corporation, Tesla, Inc. and General Motors: Nikola Corp Tesla Inc. (NKLA) (TSLA) General Motors (GM) Date Close Price ($) Close Price ($) Close Price ($) 6/30/20 67.53 215.96 25.30 7/31/20 30.00 286.15 24.89 8/31/20 40.81 498.32 29.63 9/30/20 20.48 429.01 29.59 T (a) Compute the covariance of monthly returns of General Motors with returns of Tesla over the given period. (15 points) (b) Using the covariance you have just computed in (b), calculate the correlation of monthly returns of General Motors with Tesla. Show all your formulas and inputs. (5 points)