Professor Sanchez has been teaching Principles of Economics for over 25 years. He uses the following scale for grading. Grade Numerical score Probability C 0.140 0.200 0.430 8 0.125 0.105 a. Convert the above probability distribution to a cumulative probability distribution. (Round your answers to 3 decimal places Grade P(X x) D(F) 1(0) 2(C) 3(B) 4(A) b. What is the probability of earning at least a B in Professor Sanchez's course? (Round your answer to 3 decimal places.) Probability c. What is the probability of passing Professor Sanchez's course? (Round your answer to 3 decimal places.)