The correct option is B Progesterone
Progesterone-
(i) Progesterone is a steroid hormone secreted by corpus luteum
(ii) Progesterone is responsible for maintenance of pregnancy, hence called pregnancy hormone by maintaining the endometrium wall
(iii) Hyposecretion of progesterone result in abortion. It is also called anti-abortion hormone
(iv) During pregnancy progesterone helps in attaching embryo to uterine wall, development of placenta and growth of secretory alveoli in mammary gland.
Relaxin- relaxes the ligaments in the pelvis and softens the cervix during pregnancy.
Epinephrine or adrenaline is involved in regulating visceral functions.
Estrogen helps in developing and maintaining the female reproductive system.
So, the correct answer - progesterone.