The correct answer is 4. The iliococcygeus, pubococcygeus, and coccygeus are the main muscles of the pelvic floor. These muscles form a supportive hammock-like structure and play a crucial role in supporting various organs within the pelvic region, including the bladder, uterus, and rectum, and are thus important in controlling urinary incontinence. Pelvic floor dysfunction can lead to urinary incontinence, fecal incontinence, pelvic organ prolapse, and pelvic pain, all of which can result from weakness, tightness, or impaired coordination of the pelvic floor muscles.
Although the other solutions each contain these muscles, they do not list them all.