(C) Cultural diversities
The Belgian leaders recognised the existence of regional differences and cultural diversities, and amended their constitution four times between 1970 and 1993 to work out power-sharing arrangements.
Source: Accommodation in Belgium, Chapter 1 (Power Sharing)
The answer is directly stated in the passage: "They recognised the existence of regional differences and cultural diversities." Students must remember this exact phrase, as options like "administrative" or "religious" diversities are distractors not mentioned in the text.