Correct : b,c

Explanation:
Let us analyze the possible execution sequences of threads T₁ and T₂ based on which thread acquires the shared semaphore s1 (initialized to 1) first.
Case 1: T₁ executes first 1. T₁ executes wait(s1) successfully (s1 becomes 0). 2. T₁ increments x to 1 and prints 1. 3. T₁ executes wait(s2). Since s2 = 0, T₁ blocks here. 4. If a context switch occurs, T₂ tries to execute wait(s1). Since s1 = 0, T₂ also blocks.
Both threads are permanently blocked waiting for each other, resulting in a deadlock where only 1 was printed.
→ This validates Option (c).
Case 2: T₂ executes first 1. T₂ executes wait(s1) successfully (s1 becomes 0). 2. T₂ increments x to 1 and prints 1. 3. T₂ signals s2 (s2 = 1) and signals s1 (s1 = 1), completing its execution. 4. T₁ is now free to run. It passes wait(s1), increments x to 2, and prints 2. 5. T₁ passes wait(s2) without blocking because s2 was set to 1 by T₂.
Both threads finish successfully, printing 1 followed by 2.
→ This validates Option (b).
Conclusion: The possible outcomes are b and c.