Which of the following is not a correct variable type?

Answer: Option B

Variable types in C define the kind of data that can be stored in a variable.

Option A: float - This is a correct variable type in C, used for storing single-precision floating-point numbers.

Option B: real - This is not a correct variable type in C. There is no data type called real in C.

Option C: int - This is a correct variable type in C, used for storing integers.

Option D: double - This is a correct variable type in C, used for storing double-precision floating-point numbers.

Option E: char - This is a correct variable type in C, used for storing single characters.

Therefore, the correct answer is Option B: real.