for dBm,dB,dBi, The following description is correct (). (Select 3 Answers)

for dBm,dB,dBi, The following description is correct (). (Select 3 Answers)
A . dBm: Absolute value of characterizing power
B . dBi and dBd: Characterize the relative value of gain
C . dB The relative value of characterizing power
D . If the antenna of A is 12dBi, The second antenna is 14dBi, It can be said that A is smaller than B 2dBi

Answer: A,B,C