Cut four identical squares~at~the corner out~of a $$15 cm \times 6 cm$$ rectangle. The perimeter of the 4 squares is 4 cm each. What is the perimeter of the rest~of~the shape? 
选项为:A:$$40cm$$  B:$$42cm$$  C:$$90cm$$  D:$$58cm$$  E:$$50cm$$  请回答其中一个选项.