Can you explain this answer???

Infinity Corporation acquired 80 percent of the common stock of an Egyptian company on January 1, 20X8. The goodwill associated with this acquisition was $18,350. Exchange rates at various dates during 20X8 follow: January 1, 20X8 1 E = $0.1835

December 31, 20X8 1 E = 0.1850

Average for 20X8 1 E = 0.1840 Goodwill suffered an impairment of 20 percent during the year. If the functional currency is the Egyptian Pound, how much goodwill impairment loss should be reported on Infinity's consolidated statement of income for 20X8?

Answer is C. $3,680