Turing Machine

Which of the following is/are undecidable?
MSQ

For a Turing machine M, < M > denotes an encoding of M. Consider the following two languages.

\begin{array}{ll} L1 = \{ \langle M \rangle \mid M \text{ takes more than } 2021 \text{ steps on all inputs} \} \\ L2 = \{ \langle M \rangle \mid M\text{ takes more than } 2021 \text{ steps on some input} \} \end{array}

Which one of the following options is correct?

Which of the following languages are undecidable? Note that \left \langle M \right \rangle indicates encoding of the Turing machine M.

L_1=\{\left \langle M \right \rangle|L(M)=\varnothing \}
L_2={\left \langle M,w,q \right \rangle|M on input w reaches state q in exactly 100 steps}
L_3=\{\left \langle M \right \rangle|L(M) \;is \; not \; recursive\}
L_4=\{\left \langle M \right \rangle|L(M) \;contains \; at \; least\; 21 \; members\}

Consider the following problems. L(G) denotes the language generated by a grammar G. L(M) denotes the language accepted by a machine M.

(I) For an unrestricted grammar G and a string w, whether w\in L(G)
(II) Given a Turing machine M, whether L(M) is regular
(III) Given two grammars G1 and G2, whether L(G1) = L(G2)
(IV) Given an NFA N, whether there is a deterministic PDA P such that N and P accept the same language.

Which one of the following statements is correct?

Let A and B be infinite alphabets and let # be a symbol outside both A and B. Let f be a total functional from A* to B*. We say f is computable if there exists a Turning machine M which given an input x in A*, always halts with f(x) on its tape. Let L_{f} denote the language {x#f(x)|x\inA*}. Which of the following statements is true: