This option provides the most comprehensive and strategically sound application of ITIL Demand Management. It correctly begins by analyzing business activity to define Patterns of Business Activity (PBA). It then links these PBAs to the required IT capacity. Crucially, it distinguishes between predictable and unpredictable demand, proposing a cost-effective strategy: invest in resources for predictable peaks and engage in risk-based discussions with business managers for unpredictable peaks. This aligns with the core purpose of Demand Management, which is not just to provision for all possible demand, but to manage it in a way that is aligned with business needs and financial constraints.

B: This option is too narrowly focused on the call centre, ignoring the website which is also a source of bookings and uses the same back-end service, as stated in the scenario.

C: This option incorrectly states that PBA result from IT service metrics; PBA are patterns of business activity that drive IT service usage. It also proposes the unrealistic goal of meeting all demand at all times.

D: This option jumps to process implementation and a potentially wasteful strategy of acquiring resources to exceed demand, rather than first analyzing and managing the demand in partnership with the business.

1. AXELOS, ITIL® Service Strategy, 2011 Edition. The Stationery Office.

Section 4.4.4.1, Identifying patterns of business activity (PBA): "PBA are workload profiles of one or more business activities. They represent the dynamics of the business... It is important to understand that PBA are patterns of business activity, and are not generated by the IT organization." This supports the first step in option A and refutes the premise of option C.

Section 4.4.5.2, Managing demand: "For some patterns of business activity, it may not be cost-effective to have the capacity available to meet the peak demand... In these cases, demand management may be able to influence the demand for the service." This supports the differentiated approach in option A for unpredictable demand and refutes the "meet all demand" approach in options C and D.

Figure 4.16, Core services and supporting services: This figure illustrates how business activities (like holiday bookings) drive demand for core services, which in turn drive demand for supporting infrastructure. This reinforces the need to start analysis at the business level, as described in option A.

2. AXELOS, ITIL Foundation, ITIL 4 Edition. The Stationery Office, 2019.

Section 5.2.3, Capacity and performance management practice: "The purpose of the capacity and performance management practice is to ensure that services achieve agreed and expected performance, satisfying current and future demand in a cost-effective way." This principle of cost-effectiveness supports option A's balanced approach over the expensive strategies suggested in C and D.