Taking money from a wealthy individual in order to feed a destitute family would be a Pareto improvement

Suppose that when income taxes are reduced by $400 billion, households increase consumption by 80% of the resulting change in disposable income. Suppose also that the multiplier is 2. At a given price level, the aggregate demand curve shifts to the right by

A) $320 billion. B) $400 billion. C) $640 billion. D) $800 billion.

Which statement is true?

A. Industry X has a Herfindahl-Hirschman Index of 2400.
B. Industry X has an H-H-I of 100.
C. Industry X has an H-H-I of 80.
D. Industry X has an H-H-I of 1,000.