The correct answer is: B. stranded
Overhead lines are typically made up of stranded conductors. Stranded conductors are made up of multiple smaller wires that are twisted together. This makes them more flexible and less likely to break than solid conductors.
Solid conductors are made of a single piece of wire. They are stronger than stranded conductors, but they are also more brittle and more likely to break.
Both solid and stranded conductors have their own advantages and disadvantages. The type of conductor that is used for an overhead line will depend on the specific application.
For example, solid conductors are often used for high-voltage lines, where strength is more important than flexibility. Stranded conductors are often used for low-voltage lines, where flexibility is more important than strength.
In general, stranded conductors are more common than solid conductors for overhead lines. This is because they are more flexible and less likely to break.