Alibaba Group Holding Limited reported the following figures for the year ending March 31, 2023:

4. 
   
   • Total Revenue: $112.3 billion
   • Cost of Sales: $68.4 billion
   • Operating Expenses: $28.9 billion Calculate: a) Gross profit margin. b) Operating profit margin. c) Net profit margin if the net income for the year is $22 billion.