Consider a system with 15 resources and 4 threads: $T_0, T_1, T_2$, and $T_3$. The second column in the following table shows the maximum number of resources need by each thread and the third column shows the number of resources each thread is currently holding. Let $\hat{x}$ be the maximum value of $x$ (shown below) that can still keep the system in a safe state. Which statements are correct?