The vertical Phillips curve occurs in the long run because economic agents are quick to respond to changes in the price level. the aggregate supply curve is vertical which means that: a) changes in aggregate demand will not change unemployment.
b) of lags in monetary and fiscal policies.
c) wage and price rigidities prevent changes in aggregate demand to change unemployment.

the answer is "b.the increased supply will create a surplus. "

the essential thought behind price controls is straightforward - utilize the power of law to modify the equilibrium of a market. for instance, the legislature may choose that the steel business needs to survive, and in this way pass a law to set a value floor on steel. this implies all steel sold must offer at or over the floor value, which must be set over the equilibrium cost for it to have any impact. the switch could likewise happen - the administration can choose that steel is excessively costly and set a value roof underneath its equilibrium value, with the goal that all steel must be sold at or beneath that ceiling.