Which statement is NOT correct?

According to MM theory Case $1($no corporate, no personal taxes, and no bankruptcy costs$),$ firm value can be changed by either changing the cash flows or changing the risk of the cash flows.

According to MM theory Case $1($no corporate, no personal taxes, and no bankruptcy costs$),$ the value of the firm is NOT affected by changes in the capital structure.

According to Miller's Theory $($with corporate taxes and personal taxes, and no bankruptcy costs$),$ optinal capital structure is part debt and part equity.

According to MM theory Case $2($with corporate taxes, no personal taxes, and no bankruptcy costs$),$ firms should use $100\%$ debt.