Which one of the following bonds would you select if you thought market interest rates were going to fall by $50$ basis points over the next six$$ months?

a$.$ A bond with a Macaulay duration of $6\mathrm{.}72$ years$$ that's currently being priced to yield $6\mathrm{.}91\%.$

b$.$ A bond with a Macaulay duration of $14\mathrm{.}43$ years$$ that's priced to yield $9\mathrm{.}88\%.$

c$.$ A bond with a Macaulay duration of $7\mathrm{.}42$ years$$ that's priced to yield $5\mathrm{.}74\%.$