If a staff or post cannot be found to plant as a Sutrah, what is the approved alternative in Hanafi Fiqh?

The Sutrah and Warding Off Passersby (اتخاذ السترة ودفع المار)

• The prayer must be delayed.
• Drawing a straight line on the ground in front of oneself.
• Placing a small coin on the ground.
• Praying while sitting.