Review the graph of complex number z. Plotted at (5,-5)

What is the polar form of z?
A. 5(cos(pi/4)+isin(pi/4))
B. 5sqrt2(cos(pi/4)+isin(pi/4))
C. 5(cos(-pi/4)+isin(-pi/4))
D. 5sqrt2(cos(-pi/4)+isin(-pi/4))