A 30-Year-Old Woman Complains of Swelling in Both of Her

A 30-year-old woman complains of swelling in both of her legs. She is 32 weeks pregnant, and states that she has also developed varicose veins over the past few weeks. Which of the following BEST explains the cause of this patient's signs and symptoms?

A) The gravid uterus compresses the superior vena cava, decreasing venous return to the heart.
B) Changes in the endocrine system cause peripheral edema during the late stages of pregnancy.
C) The gravid uterus compresses the pelvic and femoral vessels, decreasing venous return and causing venous stasis.
D) Changes in kidney function alter the normal electrolyte balance, causing tissue edema in the legs and feet.