Answer: Decline
Step-by-step explanation:
If U.S. goods fall in quality, less people will demand the goods which will lead to a fall in U.S. exports.
As U.S. goods are denominated in dollars, a fall in the demand for US exports is akin to a fall in demand for the US dollar.
The US dollar gets weaker so the exports at every exchange rate will fall.
Net exports is calculated by subtracting imports from exports so net exports will decline as a result of exports falling.