Which of the following statement is false?

2025

Which of the following statement is false?

  1. A.

    A recursive language is also a regular language

  2. B.

    A context free language is also a regular language

  3. C.

    A context free language is also recursive enumerable language

  4. D.

    Both (a) and (b)

Attempted by 16 students.

Show answer & explanation

Correct answer: D

Chomsky Hierarchy Overview
The Chomsky hierarchy classifies formal languages based on their generative power. The standard inclusion relationship is: Regular Languages ⊂ Context-Free Languages ⊂ Recursive Languages ⊂ Recursively Enumerable Languages.
Regular Languages are the most restrictive.
Context-Free Languages include Regular Languages.
Recursive Languages include Context-Free Languages.
Recursively Enumerable Languages include Recursive Languages.
Option Analysis
Option A claims Recursive languages are Regular. This is false because Recursive is a superset.
Option B claims Context-Free languages are Regular. This is false because Context-Free is a superset.
Option C claims Context-Free languages are Recursively Enumerable. This is true based on the hierarchy.
Option D states both A and B are false. Since A and B are indeed false statements, this option correctly identifies the inaccuracies.
Conclusion
The question asks which statement is false. Options A and B are false statements. Option D correctly identifies that both A and B are false. Therefore, Option D is the correct answer.

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