Select the correct option describing gonadotropin activity

Select the correct option describing gonadotropin activity in a normal pregnant female:

1. High level of FSH and LH stimulates the thickening of endometrium.
2. High level of FSH and LH facilitate implantation of the embryo.
3. High level of hCG stimulates the synthesis of estrogen and progesterone.
4. High level of hCG stimulates the thickening of endometrium.

Synthesis of estrogen and progesterone due to high level of hCG is a normal gonadotropic activity in a normal pregnant female.