Step 1: Analyzing statement (S1)
The Operating System (OS) is a resource manager but this is not the primary function of the OS. The OS primarily focuses on managing hardware resources such as CPU, memory, and I/O devices, ensuring that programs get access to resources in an organized and efficient way.
Thus, statement (S1) is incorrect as it is more of a supporting function rather than the primary one.
Step 2: Analyzing statement (S2)
The Operating System acts as an interface between the user and the computer. This is absolutely correct. The OS provides a user interface, such as graphical or command-line interfaces, for interacting with the hardware.
Hence, statement (S2) is correct.
Step 3: Analyzing statement (S3)
The primary function of the Operating System is not application development. Its main role is to manage hardware resources, provide an environment for applications to run, and ensure that everything operates smoothly. Application development is the job of programming environments, not the OS.
Hence, statement (S3) is incorrect.
Conclusion:
The correct answer is (3) Only S2 is correct.