America decides to use income approach to calculate GDP with the following: compensation of employees $4000 proprietors income $1500, corporate profit $1200, rental income $440, net interest $150,and has earnings of foreigners in America $50,earnings of citizens from America in foreign country $50, depreciation $40, subsidies $40 and indirect business taxes $30
Calculate the following
a national income
b GDP at market price
c GNP at factor price
d NDP at market price