What is the correct syntax for declaring a variable in C?

The correct syntax for declaring a variable in C is Option A: int variable_name;. In C, you declare a variable by specifying its data type followed by the variable name and a semicolon to terminate the declaration.

So, the correct answer is:
Option A: int variable_name;

Here's an example:

int age;

In this example, we declare an integer variable named "age." This syntax informs the compiler that "age" is of type int. Option B is incorrect because it's an assignment statement, not a declaration. Option C and Option D have incorrect syntax and are not valid ways to declare a variable in C.