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

How to prevent electrical accidents with hand tools
Never use any electrical hand tool that does not carry the underwriters laboratories seal of approval.
This seal indicates the tool has undergone extensive testing and has been found to be safe when properly maintained.
Older tools with a two-wire design should be immediately upgraded to a three-wire system by qualified personnel.

Select from:
(a). If your tool cannot be upgraded, discard it. Most power tools in use today have a three-wire system.;
(b). Older tools with a three-wire design should be immediately upgraded to a three-wire system by qualified personnel. Newer tools with a four-wire design should be immediately updated to a six-wire system by qualified personnel.;
(c). The basic system systems' systems should be shot down, primed, and kept solid. A professional process for calipers is also helpful if the machine has not been properly primed and supported by the workers.;
(d). However, you can sometimes lower your capability by changing the scanner settings and other functions as needed. Having knowledgeable technicians unmodified is an important part of maintaining safe hand tools.;
(a).