A category of formal languages that can be expressed using regular expressions and recognized by finite automata is called:

• A. Regular Language
• B. Context-Free Language
• C. Context-Sensitive Language
• D. Recursive Language

Answer: (A)

Regular languages are the set of formal languages that can be described by regular expressions and recognized by finite automata. A finite automaton, whether deterministic or nondeterministic, processes a string symbol by symbol and ends in an accepting state if the string belongs to the language. Regular expressions provide an equivalent, compact way to specify exactly those strings. Since both formalisms describe the same class of languages, any language you can write with a regular expression can be recognized by a finite automaton, and vice versa. The other categories refer to different families: context-free languages are described by context-free grammars and recognized by pushdown automata; context-sensitive languages require more powerful machines like linear-bounded automata; recursive languages are those decidable by Turing machines. Hence, the term for this category is Regular Language.