In the New Keynesian Open Economy Model, Government Spending

In the New Keynesian open economy model, government spending

A) is an effective stabilization tool with a flexible exchange rate, and an ineffective stabilization tool with a fixed exchange rate.
B) is an ineffective stabilization tool with a flexible exchange rate, and an effective stabilization tool with a fixed exchange rate; prices are flexible.
C) is an ineffective stabilization tool with a flexible exchange rate, and an ineffective stabilization tool with a fixed exchange rate; net exports depends on the relative price of foreign goods to domestic goods.
D) is an effective stabilization tool with a flexible exchange rate, and an effective stabilization tool with a fixed exchange rate.
E) always requires the support of the central bank.