4. Countries A and B are identical in all aspect, except that A is an open economy while B is a closed economy. The government in both countries decide to increase spending. Assumne that prices are fixed.How does the resulting change in GDP differs.
(A) GDP increases in B but decreases in A
(B)GDP increases in both countries, but more so in A
(C)GDP increases in both countries, but more so in B
(D)GDP increases in both countries, by the same amount