The diagram below shows the circular cross-sections of two laser beams, Beam A and Beam B, incident on a sensor screen.

What is the ratio of the cross-sectional area of Laser Beam B compared to the cross-sectional area of Laser Beam A?
5:25 : 25:2
25:425 : 425:4
2:52 : 52:5
4:254 : 254:25