The set of all strings containing at least two 0’s.

The set of all strings that begin and end with either 0 or 1.

 The set of all strings containing the substring 00.

The set of all strings containing at most two 0’s.

S->ABa, A->aab, B->Ac

 S->AB, S->BCA|0|1|2|3

All of the mentioned

S->AB|BC|CD, A->0, B->1, C->2, D->3

 None of the mentioned

All Regular grammar are context free but not vice versa

All context free grammar are regular grammar but not vice versa

Regular grammar and context free grammar are the same entity

Push Down Automata (PDA) can be used to recognize L1 and L2

Turing machine can be used to recognize all the three languages

 All the three languages are context free

 L1 is a regular language

 (01)*0 = 0(10)*

(0+1)*01(0+1)*+1*0* = (0+1)*

All of the mentioned

(0+1)*0(0+1)*1(0+1) = (0+1)*01(0+1)*

Recursively enumerable but not context free.

 Context free but not regular

Not recursive

Regular

L2 – L1 is recursively enumerable.

L2 ∩ L1 is recursively enumerable

L2 ∪ L1 is recursively enumerable

L1 – L3 is recursively enumerable

decidable and recursive

 decidable and recursively enumerable

undecidable and recursively enumerable

decidable and non-recursive