Correct option is D
On-Off Keying (OOK) is the simplest form of digital amplitude modulation, essentially a basic type of Amplitude Shift Keying (ASK). It is commonly used for transmitting binary data because it is simple to implement and inexpensive.
Mechanism: A binary "1" is represented by the presence of a carrier signal (carrier is "ON" at full amplitude), and a binary "0" is represented by the absence of the carrier signal (carrier is "OFF" or at zero amplitude).
