This rig has a folding mast that can be lowered and raised quickly.

• A. Rotary Rig
• B. Jack Knife Rig
• C. Cable Tool Rig
• D. Submersible Rig

Answer: (B)

Mobility and quick setup are being tested here. A folding, quickly raisable mast is a hallmark of a jackknife rig. Mounted on a truck or trailer, the derrick can hinge down for transport and then be raised into drilling position at the new site, allowing rapid relocation without dismantling the whole rig. The other types rely on fixed masts or different drilling methods: a rotary rig uses a fixed derrick for rotary drilling, a cable tool rig employs percussion drilling without a foldable mast, and a submersible rig is an offshore platform with a submerged hull, not a mobile, foldable mast setup.