All of the options you provided could have contributed to tensions and clashes between early European settlers and Native Americans. However, option C ("Europeans wanted the Native Americans to convert to European religions") is particularly significant, as religious conflicts often intensified misunderstandings and hostilities.
If you're looking for the most likely cause of clashes in a historical context, option C would be a strong candidate, as the European settlers' efforts to convert Native Americans to Christianity often led to conflict and resentment. Nonetheless, various factors, including resource competition and differing worldviews, contributed to the overall tensions as well.