The Union Public Service Commission (UPSC) is a constitutional body under Article 315 of the Indian Constitution. 
 UPSC conducts exams for: 
 - IAS, IPS, IFS and other prestigious Group A and B central services. 
 Option Analysis: 
 - Option A: DOPT is a coordinating agency, not the examiner. 
 - Option B: Correct. UPSC conducts the Civil Services Examination. 
 - Option C: Ministry of Home Affairs administers IPS once selected — not the exam body. 
 - Option D: SSC conducts exams for lower posts, not Civil Services.