Makowit line is wrong

the Mackowit line is wrong in cfa level 1
the argument is virtuous circle.
from description of stocks risks, authors make many reasonings to prove the description of the stock risks.

From A to B to C to A

this argument is totally wrong.

Do you mean Markowitz?

If so, what do you mean by the Markowitz line? The efficient frontier?

And why are you complaining about Level I in the Level III forum?