Multi-select problem: How does the next paragraph end?

How to use an english wheel
Understand that an english wheel is used to bend and form sheet metal to make useable parts.
It is, essentially, a rectangular frame bolted to a large stand.
The frame is shaped in the form of a closed letter' c'.

Options are: a. The top line of the center circle of the triangle shows the height of the wheel, and is stretched from top to bottom to form the' u' shape of the number d (self). Put the reed in the proper position on the round wheel.. b. A letter has an opening at the top and then one opens at the bottom. The exterior of the frame rotates itself so the ends come together at the bottom where the letters begin to slant towards each other.. c. Part of the frame can be bolted into the ground at the straight edge of the wheel. You can bend metal bent to equal the letter' c' underneath it, as well.. d. At one end of the frame are two wheels that are used to form the sheet metal. The top wheel is called the rolling wheel, while the bottom wheel is known as the anvil wheel..
d.