Given below are sentences that use discourse markers/expressions to make them complete. Identify the most appropriate discourse marker/expression and mark your answer accordingly in the Answer Sheet:

__________, one notes that in the nineteenth century an important development of reflection and questioning gained momentum.

The sentence introduces a broad historical observation about the nineteenth century. The phrase 'Generally speaking' is a standard discourse marker used to make a general statement or observation. 'Particularly speaking' is not a standard English expression. 'Otherwise' and 'Of course' do not fit the context of introducing a broad, general historical trend.

Therefore, 'Generally speaking' is the most appropriate discourse marker to complete the sentence.

Answer: Generally speaking