What statements about the beamwidth of an RF antenna are true?

What statements about the beamwidth of an RF antenna are true?
A . Horizontal and vertical beamwidth are calculated at the points in which the main lobe decreases power by 3 dB
B . Vertical beamwidth is displayed (in degree) on the antenna’s Azimuth chart.
C . When antenna gain is lower, the beamwidth is also lower in both the horizontal and vertical dimensions.
D . The beamwidth patterns on an antenna polar chart indicate the point at which the RF signal stops propagating.

Answer: A