The area of a circle whose centre is (h, k) and radius a is [MP PET 1994]

• A.            \[\pi ({{h}^{2}}+{{k}^{2}}-{{a}^{2}})\]                       
• B.            \[\pi {{a}^{2}}hk\]
• C.            \[\pi {{a}^{2}}\]                    
• D.            None of these