**Core Concept**
Relaxin is a hormone that plays a crucial role in pregnancy and parturition by relaxing the pelvic girdle and facilitating fetal head delivery. It is a peptide hormone produced by the ovaries and placenta during pregnancy.

**Why the Correct Answer is Right**
Relaxin is produced by the corpus luteum and the placenta in response to estrogen and progesterone stimulation. Its primary function is to relax the ligaments and tendons in the pelvic region, allowing for easier fetal head delivery during childbirth. Relaxin also has anti-inflammatory properties and plays a role in blood pressure regulation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because relaxin is not primarily produced by the adrenal glands.
**Option B:** This option is incorrect because while the pancreas does produce various peptides, relaxin is not one of them.
**Option C:** This option is incorrect because the pituitary gland is primarily responsible for producing anterior pituitary hormones, not relaxin.

**Clinical Pearl / High-Yield Fact**
Relaxin levels increase significantly during pregnancy, and its deficiency has been linked to complications such as preterm labor and fetal head entrapment.

**Correct Answer: C. Placenta**