Which of the following is true? O The Single European Act provided for the gradual abolition of border checks for peopl crossing national borders within the EU. The Maastricht Treaty provided for the gradual abolition of border checks for people crossing national borders within the EU. The Schengen Agreement provided for the gradual abolition of border checks for people crossing national borders within the EU. The Treaty of Rome provided for the gradual abolition of border checks for people crossing national borders within the EU