Answer is C is correct. A decision on issue of law may operate as res judicata if given on merits and if there is lack of jurisdiction or has been compromised or remanded on appeal. Therefore option (c) is the correct answer.

Answer is B is correct. Doctrine of restitution is dealt under Section 144 of CPC and based upon a well-known maxim actus curiae neminem gravabit i.e. the act of court shall harm no one. The law also imposes duty on the party to do justice to the other party in the case of erroneous judgment. Therefore option (b) is the correct answer.

Answer is C is correct. As per Section 54 of CPC Where a decree is for partition or separate possession of a share of an undivided estate assessed to the payment of revenue to the government execution should be effected by the Collector. Therefore option (c) is the correct answer.

Answer is D is correct. The general rule is that the executing court cannot go behind the decree but there are few exceptions to this whereby it has the power to go behind it. In all the circumstances mentioned above, executing court can go behind the decree. Therefore option (d) is the correct answer.

Answer is B is correct. Section 55 imposes restrictions that no dwelling house shall be entered into after sunset and before sunrise for making arrest. Therefore option (b) is the correct answer.