The ‘old laws’ protected under Article 371F refer to laws in force:

During British colonial rule
Under the Chogyal of Sikkim
Throughout the Indian independence movement
Before the merger of Sikkim with India in 1975

The correct answer is: d) Before the merger of Sikkim with India in 1975.

Article 371F of the Indian Constitution provides special status to the state of Sikkim. It states that the “existing laws in force in the State of Sikkim immediately before the commencement of this Constitution shall continue to be in force in the State subject to such modifications and adaptations as may be made by the Legislature of Sikkim”. This means that the laws that were in force in Sikkim before it became a part of India in 1975 continue to be in force today.

The other options are incorrect because they do not refer to the laws that were in force in Sikkim before it became a part of India. Option (a) refers to laws that were in force during British colonial rule. Option (b) refers to laws that were in force under the Chogyal of Sikkim. Option (c) refers to laws that were in force throughout the Indian independence movement.

I hope this answers your question. Let me know if you have any other questions.