Which action opens a file to begin I/O operations?

• A. Close file
• B. Read file
• C. Open file
• D. Write file

Answer: (C)

Opening a file creates the connection to it and gives you a file object or handle that lets the program perform input and output. This initial step is what enables any reading or writing to happen. Once a file is open, you can read data from it or write data to it. After you’re done, you close the file to flush any buffered data and release the resources. Without opening first, there’s nothing to read from or write to, and closing comes only after you’ve finished I/O. So the action that begins I/O is opening the file.