Final answer:
A sequence of successive pitches that the ear perceives as a unified whole is called a melody. It is formed through the discernment of pitch and the combination of musical notes into a sequence.
Step-by-step explanation:
A series of successive pitches perceived by the ear to form a coherent whole is known as a melody (B). The perception of frequency, which most individuals can distinguish to an excellent degree of relative pitch, forms the basis of melody. Musical notes with particular names like A-sharp, C, or E-flat constitute these melodies and are created by combinations of notes. In contrast, a harmony (A) involves the simultaneous combination of notes, a rhythm (C) refers to the pattern of sounds and silences in time, and a chord (D) is a group of notes played together.