Because Joshua and Dong Soo became close friends, a reader can infer that

Responses
A Dong Soo had a harder time understanding Joshua's culture.Dong Soo had a harder time understanding Joshua's culture.
B both accepted and appreciated their cultural differences.both accepted and appreciated their cultural differences.
C Joshua had a harder time understanding Dong Soo's culture.Joshua had a harder time understanding Dong Soo's culture.
D neither noticed the cultural differences between them.neither noticed the cultural differences between them.

B both accepted and appreciated their cultural differences.