In abdominal surgery, the Deaver retractor is preferred when:

Correct option is A

Deaver retractor is a large, curved, flat retractor. It is used to retract abdominal wall and viscera to provide deep access, especially in pelvic or abdominal cavity surgeries.
Explanation of options: (a) ✔ Correct; its shape allows safe retraction of deep structures in abdominal/pelvic surgery. (b) ✘ Skin flap elevation uses small handheld retractors, not Deaver. (c) ✘ Myomectomy uses myoma screw, not Deaver for size reduction. (d) ✘ Oral cavity retraction is done with cheek retractors or mouth gags, not Deaver.