If a taxation system charges 5 % tax on income up to OMR 30000 while 10 % on all income above OMR 30000, what will be tax liability of a person with taxable income of OMR 60000? O a. OMR 9,000 O b. OMR 4,500 O C. OMR 3,000 O d. OMR 6,000