Which of the following statements is NOT true according to the impossible trinity?

a$.$ A pegged currency can achieve stable exchange rate and free capital flow sacrificing the central bank's independent monetary policy.

b$.$ A free$-$float currency can achieve free capital flow and the central bank's independent monetary policy sacrificing stable exchange rate.

c$.$ Exchange rates among currencies that are pegged to US Dollar $($USD$)$ are unstable and hard to predict.

d$.$ Monetary independence and free capital flow can be achieved by sacrificing stable exchange rates.