Match List-I with List-II.

List-I	List-II
A. Progesterone B. Relaxin C. Melanocyte stimulating hormone D. Catecholamines	I. Pars intermedia II. Ovary III. Adrenal Medulla IV. Corpus luteum

Choose the correct answer from the options given below:

To match the biological molecules/hormones in List-I with their source organs or glands in List-II, let us analyze each term individually:

A. Progesterone: Progesterone is a steroid hormone that plays a crucial role in regulating the menstrual cycle and maintaining pregnancy. It is primarily secreted by the temporary endocrine structure known as the corpus luteum (IV), which forms in the ovary after ovulation.

B. Relaxin: Relaxin is a hormone that prepares the female body for childbirth by relaxing the ligaments in the pelvis and softening the cervix. It is primarily secreted by the corpus luteum of the ovary (II), and also by the placenta during pregnancy.

C. Melanocyte stimulating hormone (MSH): MSH is a peptide hormone responsible for regulating skin pigmentation. It is secreted by the pars intermedia (I), which is the middle lobe of the pituitary gland (hypophysis).

D. Catecholamines: Catecholamines include hormones such as epinephrine (adrenaline) and norepinephrine (noradrenaline). These are synthesized and released by the adrenal medulla (III) during stressful situations (the "fight-or-flight" response).

By matching these details, we get the following associations:
A matches with IV
B matches with II
C matches with I
D matches with III

Therefore, the correct combination is A-IV, B-II, C-I, D-III.