Answer:
C) Exports decrease, imports increase
Explanation:
If the US dollar appreciates, the US dollar has now more value per unit of foreign currency than before. For example, suppose that today 1 US dollar buys 0.8 Euro, and tomorrow, Europe is hit by a financial crisis, and the US dollar appreciates, and buys 1.2 Euro. The US dollar has appreciated, has become more expensive, becomes now more euros are needed to buy 1 US dollar.
When the US dollar gains value, domestic goods become more expensive compared to foreign goods, and this promotes imports, and reduces exports.
This is the reason why China keeps a depreciated currency: China is an export economy and the cheap Chinese currency makes exports cheaper, and imports more expensive.