Which type of pelvic tilt should precede abdominal exercises in the supine position?

The correct answer is posterior pelvic tilt.  

Pelvic tilt refers to the alignment of the pelvis in relation to the bones of the thigh and the rest of the body. The pelvis can tilt towards the back, front, or towards either side of the body.  

Posterior pelvic tilt is a postural insufficiency, however, a less usual one. The muscular imbalance in a posterior pelvic tilt is the reverse of an anterior pelvic tilt. Posterior pelvic tilt is the result of imbalances of legs and core muscles.  

i really wish i could answer this question for you