Please help I keep getting an error on excel solver

The College of Continuous Education has recently developed a lean six sigma black belt certificate program that has four courses. Each course is a 60-hour course delivered over the evenings in a semester. Course Total Hours Demanded for Professors to Teach SSBB501 Regression & Design of Experiments for Lean Six Sigma 60 SSBB502 Optimization Methods for Lean Six Sigma 60 SSBB503 Discrete Event Simulation for Lean Six Sigma 60 Note that it is possible for one course to be taught by a number of professors. For example, it is possible that SSBB501 is taught by Dr. Sfor 10 hours, then Dr. M for 50 hours; or it can be taught by Dr. R for 60 hours; or any combination of professor hours. The hours listed above are the exact amount of total hours required to deliver a course; that is, the total hours for a course cannot exceed 60, either. Three engineering professors are qualified to teach any of the sections in any of the three courses. However, due to the workload limit placed by Human Resources, they each has a limited number of hours that can be used to teach College of Continuous Education courses in a semester. Professor Hours Available to Supply CCE Courses this Semester Dr. Montgomery 100 Dr. Runger 100 Dr. Sun 100 The College of Continuous Education also requires that NO MORE THAN two professors can be picked to teach in the lean six sigma black belt certificate program this semester. Note that the effectiveness of each professor teaching the three different courses is different. The effectiveness scores are as follows. Effectiveness of Professor Montgomery teaching SSBB501 is 2 Effectiveness of Professor Montgomery teaching SSBB502 is 2 Effectiveness of Professor Montgomery teaching SSBB503 is o Effectiveness of Professor Runger teaching SSBB501 is 2 Effectiveness of Professor Runger teaching SSBB502 is 2 Effectiveness of Professor Runger teaching SSBB503 is 6 Effectiveness of Professor Sun teaching SSBB501 is 7 Effectiveness of Professor Sun teaching SSBB502 is o Effectiveness of Professor Sun teaching SSBB503 is 9 Fill out the following table with the above information: Effectiveness Dr. M Dr. R Dr. S SSBB501 SSBB502 SSBB503 What are the best allotments of the professors to the three courses to MAXIMIZE total effectiveness? Submit an excel file as attachment. 1. In the file, first write (in plain English) what are your Objective Function Constraints (make sure you include the binary constraints) Decision Variables (make sure you include the binary selection variables) 2. Build an Excel Solver model to solve the above problem. Keep your solver inputs in the excel file. What are the best allotments of the professors to the three courses