Which of the following is a form of amplitude modulation?

Standard Amplitude Modulation (AM) produces a signal that consists of a central carrier wave and two identical sidebands (upper and lower) that contain the audio information. Single Sideband (SSB) is a more efficient derivative of AM. In an SSB transmitter, the carrier wave and one of the sidebands are suppressed before transmission. This concentrates all the transmitter's power into a single sideband, making it highly efficient for long-distance voice communications. Because it is derived by removing parts of a standard AM signal, SSB is fundamentally a form of amplitude modulation. Distractors like Phase Shift Keying (PSK) or spread spectrum are entirely different modulation techniques.