In the diagram, curves $D_1$ and $S_1$ show the demand for and supply of the US dollar ($\$$) in relation to the Chinese yuan. What is the most likely reason for the demand curve for US dollars to move from $D_1$ to $D_2$?
- Aa fall in Chinese interest rates
- Ba fall in US interest rates
- Ca faster growth rate in the US economy
- Da reduction in the US government budget deficit