Which of the following statements is false?

The tangent portfolio includes risk$-$free asset.

You can construct a risk$-$free portfolio using two risky assets only if the correlation coefficient is $-1.$

The efficient diversification means that an investor should invest in any point on the capital market line.

The minimum variance portfolio is the portfolio with the lowest risk that you can construct using only risky assets.

What is the idiosyncratic risk? How can an investor refrain from the idiosyncratic risk?

It is a diversifiable risk. An investor can not refrain from the idiosyncratic risk.

It is a diversifiable risk. Studies show that holding approximately $20$ stocks would minimize the idiosyncratic risk.

It is a nondiversifiable risk. Studies show that holding approximately $20$ stocks would minimize the idiosyncratic risk.

It is a nondiversifiable risk. An investor can not refrain from the idiosyncratic risk.