Why is it dangerous to fly over hilly areas with pressure altitude?

A)
Costly
B)
Not the true altitude
C)
Not reliable
D)
Affected by temperature

Correct Answer :   Not the true altitude


Explanation : Pressure altitude is always referenced from the sea level. When flying over hilly areas, the actual altitude of the aircraft from the ground is definitely lesser than the pressure altitude, thus showing erroneous altitude readings.