Final answer:
Polyphonic singing is the correct answer, where there are multiple independent melodic lines sung simultaneously, often involving larger ensembles characteristic of the Renaissance.
Step-by-step explanation:
The type of singing that utilizes 'more than one pitch per syllable' of sung text is known as polyphonic singing. Polyphony is a musical texture characterized by the simultaneous combination of two or more independent melodic lines.
This style of music became prevalent during the Renaissance period, marking a significant change from the mostly monophonic singing of the Middle Ages.
In polyphonic music, you often find larger vocal ensembles or a combination of vocal and instrumental forces, with various parts covering the full vocal range to create a rich tapestry of sound.