Regular Language:
A regular language is a language that can be recognized by a finite automaton or expressed using regular expressions. Regular languages are a type of formal language that can be described by regular grammars. They are characterized by their simplicity and limited expressive power.

Context-Free Grammars:
Context-free grammars are a type of formal grammar that describe formal languages. They consist of a set of production rules that define the structure of strings in the language. Context-free grammars are more expressive than regular languages, as they can describe languages that regular expressions cannot.

Epigram:
Epigram is a dependently typed functional programming language that was developed for research purposes. It is known for its strong type system and expressive power. It is a Turing-complete language, meaning that it can compute anything that can be computed by a Turing machine.

Explanation:
The correct answer is option 'A', which states that a regular language is a non-Turing complete language. Regular languages are less expressive than context-free grammars and cannot express all computations that a Turing machine can perform. This is because regular languages are recognized by finite automata, which have limited computational power compared to Turing machines.

Regular languages are characterized by their simplicity and limited expressive power. They can be recognized by regular grammars or regular expressions. Regular expressions are a concise and powerful way to describe regular languages, but they lack the ability to express complex computations or handle recursive patterns.

On the other hand, context-free grammars are more expressive than regular languages. They can describe languages that regular expressions cannot, such as nested structures and recursive patterns. Context-free grammars are often used to describe the syntax of programming languages.

Epigram, mentioned in option 'C', is a Turing-complete language. It is a dependently typed functional programming language that is designed for research purposes. It has a strong type system and expressive power, allowing for complex computations and proofs to be expressed.

Therefore, the correct answer is option 'A' because regular languages are non-Turing complete, while context-free grammars and languages like Epigram are Turing complete.