David and Derek, who are visiting India together for the first time, are inclined to stereotype the locals and complain about hotels and restaurants that they feel don't measure up to American standards. Which quality that helps develop intercultural communication competence are they most evidently lacking?
a. Knowledge and skillb. Patience and perseverancec. Tolerance for ambiguityd. Open-mindedness

In communication (as well as in other areas and aspects of life), open mindedness refers to one's willingness to accept and appreciate differences. Open-minded people develop the skill to avoid stereotypes by acknowledging the existence of different views, ideas, cultures, behaviors, people etc. Open-minded people are, therefore, more flexible and less likely to dismiss chances to grow and learn from different people and situations. That is evidently lacking in David and Derek, who have "chosen" to not enjoy themselves and to not learn anything from the experience described.