The minimum usage of material X at Modern Company is 2400 Tons, and the maximum usage is 4300 Tons; normal usage is 3500 Tons. The reorder period is 3-5 weeks. Compute minimum level of material X. O a. 2400 Tons O b. 21500 Tons 4300 Tons O d. 7500 Tons Oreedo Ibri branch charges a fixed-line rental charge of OMR 2 per month. The customer's first 10 hours of telephone calls are free; after that, all calls are charged at 0.50 per minute up to a maximum of 10 hours; after that, all calls in the period are again free. What type of cost is this telephone charge? O a. Fixed Cost O b. Semi-Variable Cost O c. Direct Cost O d. Variable Cost