The passage highlights the difference between quantitative surveys (which focus on breadth/generalizability) and qualitative ethnographic studies (which focus on depth/small number of cases). Let's evaluate the options to complete this thought: Option A implies qualitative research requires larger sample sizes, which directly contradicts the previous sentence stating it focuses on a 'small number of cases'. Option B makes an unsupported claim about researcher bias, which does not logically follow the comparison of depth vs. breadth. Option C correctly bridges the thought: because qualitative studies focus deeply on a few cases, they provide 'rich, contextualised insights' that broad surveys miss. This perfectly aligns with 'prioritising depth over breadth'. Option D introduces a comparison of time consumption that isn't supported by or relevant to the established context of depth vs. generalizability.