Please help answer but explain why, thank you.

The onset of the Great Recession in the late 2000s had a large negative impact on the growth rate of the Chinese economy, which depended on export expansion. At the time, the government of China decided to shift its economic growth strategy policy away from export orientation and towards a more balanced approach that supports investment in non-tradable sectors as much as tradable sectors. What impact must this policy have had on the real exchange rate of China's yuan?

a. The policy change is likely to have had an ambiguous effect on the yuan's real exchange rate.

b. The policy change could not have had any effect on the yuan's real exchange rate.

c. The policy change must have lowered the yuan's real exchange rate.

d. The policy change must have raised the yuan's real exchange rate.