In these questions, the letters are linked in some way. Identify the relation and complete the last box. \[\text{PF}\,\,\,\text{:}\,\,\,\,\text{FP}\] \[\text{ON}\,\,\,\text{:}\,\,\,\,\text{NO}\] \[\text{LID}\,\,\,\text{:}\,\,\,\,\text{?}\]

• A.  PAN     
• B.         RAP   
• C.  DIL        
• D.         DOT