The correct option is A. Nationalism fueled rivalries between European nations. As a result, there were conflicts amongst the major European powers.
A strong sense of patriotism or loyalty to one's country is known as nationalism. Nationalists overstate the value or virtues of their own country, prioritizing it over the interests of other countries.
Thus, Early in the 20th century, nationalism was a powerful force in Europe and a major factor in the outbreak of World War I.
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