The correct answer is D. all of the mentioned.
Twitter uses a variety of programming languages to build its message server queue, including Ruby, Scala, and Java. Each language has its own strengths and weaknesses, and Twitter uses the best language for each task.
Ruby is a dynamic, interpreted language that is easy to learn and use. It is often used for web development, and Twitter uses it for some of its back-end services.
Scala is a functional programming language that is designed to be scalable and efficient. It is often used for large-scale data processing, and Twitter uses it for its message server queue.
Java is a general-purpose programming language that is widely used in enterprise applications. It is known for its stability and security, and Twitter uses it for some of its core services.
By using a variety of programming languages, Twitter is able to build a message server queue that is both efficient and reliable.