D  
Levator ani arises from the body of the pubis, the arcus tendineus (a thickening of obturator internus fascia) and the ischial spine; these origins lie below the pelvic brim, so the muscle is not attached to the brim itself. It converges downward and medially, is composed chiefly of the pubococcygeus (incl. puborectalis) and iliococcygeus, and forms a sling that supports pelvic viscera [Strohbehn et al., 1996, PMID 8559539; Occelli et al., 2001, PMID 11451551].