Which below is not a kind of communication barrier from cultural differences?

A、Xiao Li's manager is from Hong Kong. Because Xiao Li does not understand Cantonese, he sometimes cannot accurately understand the real meaning of his manager's talk.
B、Xiao Li the trainee, sometimes cannot understand the jokes from his colleagues who have been worked in this hotel for more than 5 years.
C、Xiao Li is more introverted and rarely communicates with colleagues in other departments.
D、Xiao Li graduated with a bachelor degree. At work, he found that he could not clearly understand his colleagues who have master degree when they were discussing some technical issues.