If the economy has unemployed workers but cannot produce any more real output then the government

has to raise taxation if it wants to achieve full employment.
has to increase net spending until the spending gap is filled if it wants to achieve full employment.
will generate inflation if it wants to achieve full employment.

Answer: has to raise taxation if it wants to achieve full employment.

Please read Bad luck if you are poor! for more information or post a comment if you are unsure.