This normally depends upon the size of the sheep. All four answers will work. There are many different ways to restrain a sheep, depending upon what you need to do to it. Once you've caught the sheep, you can press it against a wall or straddle it to limit its movement. A halter is one of the easiest ways to restrain a sheep for treatment or close inspection. If you want to tip a sheep then
a. tilting them onto their rump would work best.