Answer: LULLABIES!
Explanation: I got I similar question and I got it right!
It would say that the technique that was discontinued during the swing era was Collective improvisation (option B) This might be because improvisation was connected to Jazz and Free Jazz music. Swing jazz is based on the off-beat or music pulse.
The Romans constructed aqueducts throughout their Republic and later Empire, to bring water from outside sources into cities and towns. ... Aqueducts moved water through gravity alone, along a slight overall downward gradient within conduits of stone, brick, or concrete; the steeper the gradient, the faster the flow.