Read the paragraph. [1] Our house was once a stop on the Underground Railroad. [2] It was common for an enslaved person to stop there on their way to the North. [3] The Underground Railroad were a network of hiding places. [4] The cellar beneath our house has a secret door that was installed to trick slave catchers. Which sentence has a subject-verb agreement error? sentence 1 sentence 2 sentence 3 sentence 4