Which of the following question is decidable?

Group of answer choices

Whether or not the two CFGs are defining the same language.

None of the above.

Whether or not the compliement of a context$-$free language is context$-$free language.

Whether or not a given CFG defines all strings of a$\text{'}$s and b$\text{'}$s$.$

Whether or not the intersection of two context$-$free languages are empty.