Let L1 be a regular language, L2 be a deterministic context-free language and L3 a recursively enumerable, but not recursive, language. Which one of the following statements is false?

Automata theory (also known as Theory Of Computation) is a theoretical branch of Computer Science and Mathematics, which mainly deals with the logic of computation with respect to simple machines, referred to as automata. Automata* enables scientists to understand how machines compute the functions and solve problems.
Theory of Computation is very important in compiler design as it helps in writing efficient algorithms, which help make efficient compiler construcion.