What is the perimeter of the polygon in the diagram?
A2√(a-b)^2
B4(a+b)^2
C2(a^2 + b^2)
D4√(a^2 + b^2)
A2√(a-b)^2
B4(a+b)^2
C2(a^2 + b^2)
D4√(a^2 + b^2)