Radio Altimeter
Came across this question in ATPL studies:
The radio altimeter receives information from:
a) The gound within an ellipse of 30 degrees in the for and aft axis and 60 degrees in the athwartships axis beneath the aircraft
b) The ground within a 30 degree cone directly beneath the aircraft
c) The ground directly beneath the aircraft
d) The ground below the aircraft within a narrow cone angled 70 degrees down from the horizontal
The poor spelling and grammar are not mine, this is exactly how it was written
Which is the least wrong answer and why?