It was very big and could be seen just by walking down the streets, You said which statment explains the irony of it, but you didn't give me multiple choice, so this is all I could answer to
The answer is C because the relative pronoun "that" is connecting "friend" to a clause. A relative pronoun connects nouns (friend) to phrases or clauses.
Yea I’ve read it what’s your question about the book?
I think that it is called a Pronoun Reference.