Hormone responsible for maintenance of pregnancy in early stages is:
Progesterone (A) is the right choice. This sits at the heart of Reproductive System: the wording points straight to what is happening in the tissue or organ system. A useful study habit is to ask what the structure or process is for: Progesterone is the option that correctly names the structure, process, or principle asked for in Reproductive System. That reasoning supports Progesterone. One solid sentence about why this works is enough for recall — you do not need a long essay for every MCQ. When you practise, cover the choices first, write Progesterone from memory, then reveal the letter — that habit builds real recall for Reproductive System.
Ref: Animal physiology is Unit 7 of the CSIR NET Life Science Syllabus, covering core body systems. It accounts for roughly 10% of the total marks in Sections B and C.