Q Compressiblity error
A Causes overreading of the ASI at all levels whenever TAS exceeds 300kt.
B Causes overreading of the ASI whenever CAS exceeds 300kt.
C is calibrated out of the ASI at MSL ISA conditions and only causes overeading when air density is decreased and CAS exceeds 300kt.
D is calibrated out of the ASI at MSL ISA conditions and only causes overeading when air density is decreased and TAS exceeds 300kt.
As per my understanding answer is one of A or D as compressibility error occurs at TAS more than 300kts, also airspeed indicator is calibrated at seal level for density error, but I am not sure if its A or D.
Please list the answer and the reason also. Thanks alot in advance for the help 