A. On a workout bench. Note - if your feet can't stay flat on the ground when lying all the way back you CAN come onto the toes. However a flat foot is better. If you have access you can try putting plates to help bring the floor to you.
B. From the floor - A slightly less in...
A. Bodyweight. Holding hands on hips, or reaching out in front of you like in the good morning demo
B. With weights. You can hold onto 1 weight in hand of opposite leg working (the flat foot) or hold onto two weights