Final answer:
The correct answer is C) underwent/has been questioned, reflecting the timing of industrial changes in Sweden and their ongoing effects.
Step-by-step explanation:
The correct answer to the question "Since Swedish industrial relationships ___ so many fundamental changes, it is hardly surprising that the existence of a 'Swedish model'" is C) underwent/has been questioned. The sentence calls for past simple and present perfect to indicate that Swedish industrial relations experienced changes in the past and the effects or questioning of these changes continue to the present.
The industrialization period has indeed led to profound changes in society, leading some to question the Swedish model. For instance, the transition from an agrarian to an industrial economy has consequently influenced the social structure, government involvement in the private sector, global trade, cultural shifts from modernity to postmodernity, and even education systems. This interconnected impact across social institutions is critical to understanding the dynamics of change in industrial relationships.