Asuccession of single tones or pitches perceived as a unit is called:

A succession of single tones or pitches perceived as a unit is called a melody. It is a linear succesion of tones in music that is seen as one single entity. It is a combination of rhythm, pitch and tonal color. Melodies usually has one ormore motifs or phrases that are being repeated all throughout a composition. Melodies are characterized by the melodic motion it posses , the pitch, intervals between the pitches, continuity and pitch range. Due to the a wide range of melodies that can be made from tones, differet genres of music arise. Examples are Jazz, Rock music, Classical, pop, R&B and the like. 

Iagree c would be the answer