E9C03 - Amateur Extra Class

E9C03 : What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?
A Omni-directional
B Cardioid
C A figure-eight broadside to the axis of the array
D A figure-eight end-fire along the axis of the array
Correct Answer: A figure-eight broadside to the axis of the array