Which line causes a compilation error? 05/21/2017 – by Mod_GuideK 0 Given: Which line causes a compilation error? A. line x1 B. line x2 C. line x3 D. line x4 SHOW ANSWERSCorrect Answer: B Explanation/Reference: Explanation: The variable x2 is used before it has been declared. Download Printable PDF. VALID exam to help you PASS.