This option provides the most comprehensive and strategically aligned approach according to ITIL principles. It correctly recognizes that IT resources are shared and require a sophisticated costing model. It directly addresses the board's request by costing the various service provision options, calculating the Return on Investment (ROI) using projected revenues, and feeding this crucial financial analysis into the Service Portfolio Management (SPM) process. This enables an informed, value-based decision on which options to pursue and provides the foundation for a robust business case, which is the primary purpose of these activities.

A: The scenario states the organization has a "good appreciation of its IT costs," implying that foundational financial management processes already exist, making this option redundant.

B: Sharing investment costs equally is an arbitrary and inaccurate method of cost allocation that would lead to a flawed ROI calculation and poor investment decisions.

C: This option incorrectly introduces outsourcing, which is not mentioned in the scenario's scope, and misidentifies Service Level Agreements (SLAs) as the primary tool for usage-based costing.

1. AXELOS, ITIL® Service Strategy: 2011 Edition, TSO (The Stationery Office), 2011.

Section 4.3.5.3 (The Analyze phase): This section of the Service Portfolio Management process describes how potential services are analyzed to understand their value proposition. It states, "The business case is updated with more detailed cost/benefit information... This includes a detailed risk, resource and financial analysis." This directly supports costing options, calculating ROI, and using it for comparison within SPM, as described in option D.

Section 5.5 (Business Case): This section details the structure of a business case, emphasizing the inclusion of "financial analysis (costs, benefits, ROI)." This confirms that calculating ROI for different options is a standard and necessary step for making investment decisions.

Section 5.4.3.2 (Cost models): This section explains that cost models are used to calculate the cost of services, especially in environments with shared resources. This refutes the simplistic "equal sharing" approach in option B.

2. AXELOS, ITIL® Foundation, ITIL 4 Edition, TSO (The Stationery Office), 2019.

Section 5.2.11 (Portfolio management): This practice guide states that portfolio management involves "deciding where to invest" and "reviewing the active portfolio" to ensure it aligns with strategic objectives and provides value. The process described in option D is a core input to this practice.

Section 5.2.16 (Service financial management): This practice guide notes its purpose is to support "strategies and plans... by ensuring that the organization’s financial resources and investments are being used effectively." This includes activities like "funding" and "costing," which are central to the financial review described in the scenario and option D.