The correct answer is A (0%). The real exchange rate change is calculated using the formula:

$$\text{Real Exchange Rate Change} = \left( \frac{1 + \Delta P_f}{1 + \Delta P_d} \right) \times (1 + \Delta S) - 1$$

Where:

• $\Delta P_f$ is the foreign price change (6% for the Eurozone),
• $\Delta P_d$ is the domestic price change (2% for the US),
• $\Delta S$ is the nominal exchange rate change (-4% for USD/EUR).

Plugging in the values:

$$\left( \frac{1 + 0.06}{1 + 0.02} \right) \times (1 - 0.04) - 1 \approx 0\%$$

Thus, the real exchange rate remains approximately unchanged. Options B and C are incorrect due to miscalculations involving additive assumptions or misinterpretations of the nominal exchange rate change.