What is the lateral surface area of the pyramid?

Question

A square pyramid has a base perimeter x, and the slant height is half of the perimeter. What is the lateral surface area of the pyramid?                                                                                              

      (a) x²                                                                             (b) 0.75 x²

      (c) 0.50 x²                                                                  (d) 0.25 x²