Answer & Explanation:
According to Friedman, an important characteristic of money is that, in the long run it is considered as 'neutral', which means that it only impact nominal variables but do not have an effect on real ones. Then, the monetary policy that operates through the money supply will only impacts nominal GDP, price levels and wages.
a. Nominal GDP- Can be affected by money supply
b. Real GDP- NOT affected
c. Inflation- Can be affected
d. Unemployment- NOT affected