Apple Corporation reported the following figures for the year ending December 31, 2023:

 - Net Sales: $1,000,000

 - Cost of Goods Sold (COGS): $400,000

 - Operating Expenses: $200,000

 Calculate:

 a) Gross profit margin.

 b) Operating profit margin.

 c) Net profit margin if the net income for the year is $300,000.