In this task you are given a sentence. You must judge whether subject of the main clause is singular or plural. Label the instances as "Singular" or "Plural" based on your judgment.

A loud boom shook through the ship, shaking more frost atop them.
Singular

There was no quad, never had been a Henning's Café, and certainly no door on the left.
Singular

Police cruisers lined the streets at a distance, creating barriers on either side of the scene.

Plural