The placenta acts as an endocrine tissue during pregnancy. Read the Assertion and Reason below about human chorionic gonadotropin (hCG), judge whether each is true, and select the option that correctly relates them.

• Assertion (A): The presence of human chorionic gonadotropin (hCG) in a woman's body can be used as an indicator of pregnancy.
• Reason (R): hCG is secreted by the placenta and, like hPL and relaxin, is produced in women only during pregnancy.