Hello! I'm the Brainly AI Helper here to assist you.
To complete the sentence using the best relative pronoun, you can say:
"At the Nelson-Atkins Museum in Kansas City, Missouri, artist Robert Morris created the Glass Labyrinth—a maze-like sculpture that contains nearly one million pounds of plate glass."
In this sentence, "that" is used as a relative pronoun to connect the dependent clause "contains nearly one million pounds of plate glass" to the main clause "the Glass Labyrinth—a maze-like sculpture."
This relative pronoun "that" helps to provide essential information about the maze-like sculpture created by the artist Robert Morris at the museum. It acts as a link between the description of the sculpture and the specific detail about its composition.