Answer:
The answer is string quartet and double bass, with frequent modulations, wanders trough series of foreign keys.
Explanation:
The serenade is a four movement piece with a string quartet and double bass. It is from the Classical Era and the first movement is in sonata-allegro form. The opening of the first movement of Eine Kleine Nachtmusik begins with a marchlike theme that rapidly ascends to its peak, a rocket theme, them turns downward at the same rate.
The overall form of the third movement of the serenade is ABA, with frequent modulations, wanders trough series of foreign keys.