A block P of mass m is placed on a frictionless horizontal surface. Another block Q of same mass is kept on P and connected to the wall with the help of a spring of spring constant k as shown in the figure. \[{{\mu }_{s}}\] is the coefficient of friction between P and Q. The blocks move together performing SHM of amplitude A. The maximum value of the friction force between P and Q is [IIT-JEE (Screening) 2004]

• A.                 \[kA\]                
• B.                 \[\frac{kA}{2}\]                
• C.             Zero
• D. \[{{\mu }_{s}}\,mg\]