1. which of the following is an example of a ground in a building?\na pipe to the ground\na metal rod in the…

Brief Explanations:

In electrical - building systems, a ground is a connection to the earth. A pipe to the ground can serve as a path for electrical current to flow safely into the earth, acting as a ground. A metal rod in the air is not a ground as it has no connection to the earth. An extra electrical cord is not a ground. A plastic rod is an insulator and cannot be a ground.

Answer:

A. A pipe to the ground