QUESTION $4$

Given a security classification $\frac{?}{{?}_1}\frac{,}{{?}_2},L\frac{3}{{?}_4}>xL3YL1xYYxYxY\frac{Y}{{?}_1},$ where $\frac{?}{{?}_1}\frac{,}{{?}_2},L3,$ and $\frac{?}{{?}_4}$ are security levels, and $">"$ means dominates.

$If$ a subject $x\text{'}s$ security level $isL3,$ and $an$ object $Y\text{'}s$ security level $isL1.$ According $to$ the Mandatory Access Control $(MAC)$ policy, which $of$ the following statements $is$ correct?

$A.x$ cannot read $Y$ nor write $toY.$

$B.x$ can both read and write $toY$

$C.x$ can read $Y.$

$D.X$ can write $toY.$