​Gastric bypass surgery

A) ​usually produces massive weight loss.
B) ​carries health risks from the surgical procedure.
C) ​has replaced liposuction as the most common surgical approach to weight control.
D) ​both a and B

Gastric bypass surgery generally results in significant weight loss, but it also carries risks and potential complications associated with any surgical procedure, such as bleeding and infection. Therefore, both option A and B are correct. However, gastric bypass surgery is not a replacement for liposuction as they are two different procedures with different goals. Therefore, option C is incorrect.