Answer:
c. appreciate
Step-by-step explanation:
If the Federal Reserve reduces the interest rate of the US dollar this will lead to lower cost of funds, more people will borrow money and this increases money supplied to the economy.
Excess money will pursue less goods leading to inflation where the purchasing power of the US dollar will reduce.
All things being equal the value of the euro will appreciate against the US dollar if interest rate is decreased.
As the euro strengths against the US dollar, one will need less euros to purchase the weakened dollar.