FOR OPTION 1) Explaination is if a program is given then it is made from logic and we know that the limitation of logic is TM(turing machine) so it may be possible that TM produce output or it may be hang(means doesnot produce output) hence option 1 is undecidiable…..
FOR OPTION 2) Explaination is context free language is decidiable in M,E,FINITE(membership, empiteness and finiteness) but it is asking about complement hence it is not decidiable…
FOR OPTION 3) Explaination is regular language is decidialbe in each and every domain since it is minimum language in chomskey hierarchy….hence option c is decidiable.
FOR OPTION 4) Explaination is recursive language is closed under C,M(complement and membership) and in the question it is asking about complement hence it is decidiable..
CONCLUSION: Statement 3 and 4 are decidiable but option 1 and 2 are not decidiable hence answer is D…..thank you…..