The Regional Institute of Medical Sciences (RIMS) is a major healthcare institution located in:

Imphal
Churachandpur
Ukhrul
Jiribam

The correct answer is: a) Imphal.

The Regional Institute of Medical Sciences (RIMS) is a major healthcare institution located in Imphal, the capital of Manipur, India. It was established in 1987 and is the only tertiary care hospital in the state. The institute offers a wide range of medical and surgical services, including emergency care, intensive care, and cancer treatment. It also has a teaching hospital and a medical college.

The other options are incorrect because they are not the locations of RIMS. Churachandpur is a town in the Churachandpur district of Manipur. Ukhrul is a town in the Ukhrul district of Manipur. Jiribam is a town in the Jiribam district of Manipur.