The correct answer is (b). Machine language is the only language that is written in binary code. It is the lowest level of programming language and is directly understood by the computer. All other programming languages are compiled or interpreted into machine language before they can be executed by the computer.

Pascal is a high-level programming language that is designed for structured programming. It is relatively easy to learn and use, and it is often used in teaching computer science.

C is a general-purpose programming language that is used for a wide variety of applications. It is a powerful language that is relatively efficient, and it is often used in system programming.

is a high-level programming language that is designed for functional programming. It is a relatively new language, but it has gained popularity in recent years.

In conclusion, the only language that is written in binary code is machine language. All other programming languages are compiled or interpreted into machine language before they can be executed by the computer.