An Important Distinction Between the Classical and Keynes's View of the Economy

An important distinction between the classical and Keynes's view of the economy is that

A) Keynes stressed the supply side of an economy while classical economists stressed the demand side of the economy.
B) classical economists argued that output gaps were caused by shifts in the long-run aggregate supply while Keynes' maintained that output gaps were created by shifts in aggregate demand.
C) Keynes stressed the demand side of an economy while classical economists stressed the supply side of the economy.
D) classical economists argued that output gaps were caused by shifts in the long-run aggregate supply while Keynes' maintained that output gaps were created by wage and price rigidities.