A decision to radically alter a business' salary structure is most likely an example of a:

The decision to radically alter a business's salary structure is primarily related to a significant change in costs. When a company adjusts its salary structure, it directly impacts labor costs, which are often one of the largest expenses for a business. Such a change can lead to a "cost blow-up," where the fluctuations in expenditure can substantially alter the financial dynamics of the business.

This type of decision can affect employee morale, retention, and overall productivity, which in turn may also impact revenue and profits. However, the core issue revolves around the management and alteration of costs. By redesigning the salary structure, the company is essentially undergoing a substantial adjustment in how it allocates financial resources to its workforce, hence the label of a "cost blow-up" accurately reflects the nature of this decision.

In contrast, while a "business model blow-up" pertains to a revolutionary change in how a company creates, delivers, or captures value, that does not specifically focus on costs in the same manner as a salary structure modification. Similarly, "revenue" and "profit blow-ups" relate more to fluctuations in income rather than the operational costs associated with employee compensation. Thus, the most fitting characterization of the decision to alter the salary structure is clearly identified as a