If Labour Markets Had Perfectly Flexible Wages,as the Market-Clearing Theories

If labour markets had perfectly flexible wages,as the market-clearing theories suggest,involuntary unemployment would

A) rise when the labour demand curve shifts to the left.
B) rise when the labour demand curve shifts to the right.
C) rise when the labour supply curve shifts to the left.
D) rise when the labour supply curve shifts to the right.
E) not exist.