Task: Wrong Candidate Generation
Input (English): Context: So ... yesterday my shower drain backed up and flooded my room . Today my carpet stinks . I fixed the drain myself but my room smells like a mixture of mildew and sewage . It 's still damp , too . 
Question: Why did the writer 's shower drain back up ? 
Correct Answer: None of the above choices .
Output (English): Because the writer 's carpet stinks .