Final answer:
Option d) 'An increase in the dollar's value hurts a U.S. firm's domestic sales because foreign competitors can increase their sales to U.S. customers' is an example of economic exposure for a U.S. firm.
Step-by-step explanation:
Economic exposure refers to the risk that a firm's financial position and cash flows may be affected by changes in exchange rates. From the given options, option d) 'An increase in the dollar's value hurts a U.S. firm's domestic sales because foreign competitors can increase their sales to U.S. customers' is an example of economic exposure for a U.S. firm. This is because when the dollar strengthens, it makes the firm's products relatively more expensive for foreign customers, leading to a decrease in domestic sales.