A. is an opening to a story that establishes the context and gives background details, often some earlier story that ties into the main one.
OR
B. is a high-level computer programming language first devised for artificial intelligence applications.
Of course its B. But, what REALLY IS Prolog?
There are different approaches to software development other than using a traditional language. Other types of useful languages exist, such as Prolog. Prolog is a logic programming language from the 1970s that is still one of the main programming languages used in artificial intelligence and computational linguistics. Prolog is Turing complete and uses logic to answer complex questions.
A popular implementation of Prolog is SWI-Prolog. SWI-Prolog is an open-source, free version of Prolog that you can even try online. Some developers use SWI-Prolog to develop web applications. Check out this tutorial to see how web development is possible with SWI-Prolog.