What was the period that immediately preceded the ars nova called?

The correct answer is
the ars antiqua

Basically, it's fancy terms for old and new. Antiqua is from antique and antiquity and means old, and it precedes the ars nova which means new. Basically, both mean new art and old art, in relation to time. Both are old art now since the ars nova period was in the middle ages.

The answer to the question is a.