Which of the following is true?

Question $56$ options:

The Black$-$Scholes$-$Merton formula requires cumulative probabilities from the lognormal distribution.

The Black$-$Scholes$-$Merton model combined with put$-$call parity give the theoretical price of an American put option.

A riskless hedge requires more shares of stock than call options.

The Black$-$Scholes$-$Merton model assumes that the volatility does not change throughout the option's life.