The correct answer is D. All of the above.
Declaring variables has several advantages:
- It avoids errors from misspelled variable names. The compiler can check that the variable name is declared before it is used, and that it is used in a consistent way.
- It helps the linker work efficiently. The linker can resolve references to variables by looking at the variable declarations.
- It simplifies the writing of very short programs. By declaring variables, you can avoid having to repeat the same variable name multiple times in a program.
Option A is correct because declaring variables helps to avoid errors from misspelled variable names. The compiler can check that the variable name is declared before it is used, and that it is used in a consistent way.
Option B is correct because declaring variables helps the linker work efficiently. The linker can resolve references to variables by looking at the variable declarations.
Option C is correct because declaring variables can simplify the writing of very short programs. By declaring variables, you can avoid having to repeat the same variable name multiple times in a program.
Option E is incorrect because declaring variables has several advantages.