40321

Solution B) 16cm

I have included a diagram and here I will explain it
I have called the width of one rectangle 'a' and the length 'b'
The width of the whole shape is b
The length of the whole shape is 2a+b
60 = b(2a+b)
After trial and error I have worked out that a=2
B= 6
So the perimeter of one rectangle is 2(2+6) = 16cm