What is the meaning of across the moon like a prison bar

The mast looks like it imprisons the moon, like the British imprison the colonists.

Explanation:

According to a different source, these are the options that come qith this question:

This refers to the poem "Paul Revere's Ride" by  Henry Wadsworth Longfellow. In this poem, the author describes the famous ride of Paul Revere, where he managed to warn the colonists of the fact that the British were coming. When the author describes how the mast of the British ship imprisons the moon, this is intended to be a symbol of how the colonists are also imprisoned by the British.