Which two explanations of DTMF dialing are true? (Choose two)

Which two explanations of DTMF dialing are true? (Choose two)
A . DTMF dialing consists of simultaneous voice-band tones generated when a button is pressed on a telephone
B . The use of DTMF enables support for advanced telephony services
C . DTMF: dialing uses INVITE messages to signal when the first digit is pressed in a new call
D . DTMF: dialing consists of a simultaneous digital-band pulse generated when a button is pressed on a telephone.
E . DMTF dialing is based on rows and columns of Low frequency modulation There are 4 rows, and 5 columns, with 2 farthest night columns being used for reserved applications

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Answer: AB