Purchasing Power Drives the Choice Steps:

• Identify key factors: pre-tax income, after-tax income, and cost of living for Germany vs. England.
• Note lower pre-tax in Germany suggests initially less attractive, but higher after-tax indicates lower German taxes.
• Lower cost of England means higher costs in Germany, reducing purchasing power unless offset.
• Assess net benefit: higher after-tax in Germany compensates for higher costs, making real income superior.

Why D is correct:

• Higher after-tax income in Germany boosts disposable income, outweighing higher costs via real income formula (after-tax income / cost-of-living index), favoring Germany.

Why the others are wrong:

• A: Higher incomes and lower German costs make choice obvious, not a compelling "cause" amid trade-offs.
• B: Identical to D, but lacks unique tax-cost dynamic emphasized here.
• C: Lower incomes and higher German costs reduce purchasing power, favoring England.

Final answer: D