11. Professor Sanchez has been teaching Principles of Economics for over 25 years. He uses the following scale for grading. Grade Numerical Score Probability A 4 0. 10 B 3 0.30 C 2 0.40 D 0. 10 O 0.10 a. Depict the above probability distribution graphically. Comment on whether or not the probability distribution is symmetric. b. Convert the above probability distribution to a cumulative probability distribution. c. What is the probability of earning at least a B in Professor Sanchez's course? d. What is the probability of passing Professor Sanchez's course