Between 2017 and 2018,if an Economy's Exports Rise by $8

Multiple Choice

Between 2017 and 2018,if an economy's exports rise by $8 billion and its imports fall by $8 billion,by how much will GDP change between the two years,all else equal?

A) Net exports will increase GDP by $8 billion.
B) The increase in exports is offset by the decrease in imports,so there is no change in net exports and no effect on GDP.
C) Net exports will increase GDP by $16 billion.
D) Net exports will decrease GDP by $8 billion.