Which sentence is an example of an oxymoron?

A.
There was a swoosh then a plop when the pot of soup fell on the kitchen floor.
B.
The cat purred and stretched its limbs as far as the four corners of the room.
C.
There was a roaring silence outside after the storm swept through the town.
D.
The baby's cries pierced through the walls of the house and woke everyone up.