Which of the following is correct about Social Security and Medicare taxes?

The $2024$ tax rate for social security is $6\mathrm{.}2\%$ for the employer and $6\mathrm{.}2\%$ for the employee, or $12\mathrm{.}4\%$ to

II$.$ The $2024$ rate for Medicare is $1\mathrm{.}45\%$ for the employer and $1\mathrm{.}45\%$ for the employee, or $2\mathrm{.}9\%$ total.

III. Employers are responsible for withholding the $0\mathrm{.}9\%$ Additional Medicare Tax on an individual's wages

$1$

II

II and III

I, II$,$ and III