Q9

Consider the following threads, $\text{T}_{1}, \text{T}_{2},$ and $\text{T}_{3}$ executing on a single processor, synchronized using three binary semaphore variables, $\text{S}_{1}, \text{S}_{2},$ and $\text{S}_{3},$ operated upon using standard $\textsf{wait}()$ and $\textsf{signal}().$ The threads can be context switched in any order and at any time.

$$\begin{array}{|c|c|c|} \hline \text{T}_{1} & \text{T}_{2} & \text{T}_{3} \\\hline \text{while(true)} \{ & \text{while(true)} \{& \text{while(true)} \{ \\ \text{wait(S}_{3}); & \text{wait(S}_{1}); & \text{wait(S}_{2}); \\ \text{print(“C”)}; & \text{print(“B”)}; & \text{print(“A”)}; \\ \text{signal(S}_{2}); \} & \text{signal(S}_{3}); \} & \text{signal(S}_{1}); \} \\\hline \end{array}$$

Which initialization of the semaphores would print the sequence $\text{BCABCABCA} \dots ?$