Explanation:

The Corpus luteum (meaning 'yellow body') is a temporary endocrine structure that forms in the female Ovary (Option B) after the ovulation of an egg from the ovarian follicle. It plays a crucial role in hormone production, primarily progesterone, which is vital for maintaining pregnancy. It is not found in the Brain (Option A), Pancreas (Option C), or Liver (Option D), which are organs with entirely different functions.