What does the format specifier %10d in printf("%10d", num); do?

Explanation:

The format specifier %10d in the printf function is used to define the output formatting of an integer variable in C programming. In this context, it specifies that the integer should be printed within a field width of 10 characters. This means the number will be right-aligned within a space of 10 characters. If the number has fewer than 10 digits, the extra spaces will be filled with spaces (not zeros) on the left side. This is a common technique used to ensure that numbers are aligned properly in tabular data or formatted output.

Correct Option:

The correct option is Option 2: Prints the number in a field of 10 columns. This option accurately describes the behavior of the format specifier %10d. It ensures that the integer is displayed within a field width of 10 characters, right-aligned, with any extra space on the left filled with spaces.