The correct answer is D. (i), (ii) and (iii) are correct.
A derrick crane is a type of crane that uses a rotating arm to lift and move heavy objects. The main parts of a derrick crane are the mast, boom, bull wheel, and winch.
- The mast is the vertical pole that supports the boom.
- The boom is the horizontal arm that extends from the mast and supports the load.
- The bull wheel is a large wheel that is used to rotate the boom.
- The winch is a machine that is used to raise and lower the load.
The jack is not a part of a derrick crane. It is a tool that is used to lift heavy objects.