In each of the following cases, in the short run, determine whether the events cause a shift of a curve or a movement along a curve. Determine which curve is involved and the direction of the change.
a) As a result of new discoveries of iron ore used to make steel, producers now pay less for steel, a major commodity and used in production.
b) An increase in the money supply by the Federal Reserve increases the quantity of money that people wish to lend, lowering interest rates.
c) Greater union activity leads to higher nominal wages.
d) A fall in the aggregate price level increases the purchasing power of households' and firms' money holdings. As a result, they borrow less and lend more.