Let G₁ and G₂ be arbitrary context free languages and R an arbitrary regular language.

Consider the following problems:

(A) Is L(G₁) = L(G₂)?

(B) Is L(G₂) ≤ L(G₁)?

(C) Is L(G₁) = R?

Which of the problems are undecidable ?

Choose the correct answer from the options given below: