a) The author claims that there are two roads to modern nation building: one involving an internal transformation, and the other involving the struggle of non-ruling ethnic groups in multi-ethnic empires.
b) An example of a nationalist movement that would fit the pattern described by the author in the second paragraph is the Indian independence movement led by Mahatma Gandhi in the early 20th century.
c) One limitation of the author's argument as a source for understanding the different types of nationalism that developed around the world in the period since 1750 is that it focuses primarily on European examples, and does not account for the different types of nationalist movements that have arisen in other parts of the world. Furthermore, the author does not discuss the influence of imperialism and colonialism on the development of nationalism in different regions, which is an important factor to consider.