Final answer:
According to PMI guidelines for creating a WBS, 'Software' is the least preferable choice for a WBS item because it is not action-oriented and does not represent a deliverable or specific work activity.
Step-by-step explanation:
The Work Breakdown Structure (WBS) is a key project deliverable that organizes the team's work into manageable sections. According to the Project Management Institute (PMI), each element of the WBS should represent definable tasks that can be completed independently. Therefore, the wording for a WBS item should reflect a verifiable outcome or deliverable.
In this case, the options provided are:
Looking at these options, 'Software' is the least preferable choice as it is simply a noun and does not represent a deliverable or a specific work activity. Alternatively, 'Install software', 'Software installation', and 'Software training' are action-oriented and represent distinct work packages or activities, fitting into the PMI's best practices for WBS items.