Q. In an open economy, the national income (Y) of the economy is:(C,I,G,X,M stand for consumption, Investment, Govt. Expenditure, total exports and total imports respectively ) 

1. Y=C+I+G+X
2. Y= C+I+G-X+M
3. Y= C+I+G+(X-M)
4. Y=C+I-G+X-M