Which of the following SOC report subtypes spans a period of time?

The correct answer is that the subtype which spans a period of time is Type II. Type II SOC reports evaluate the effectiveness of a service organization's controls over a specified period, typically covering a minimum of six months. This type of report assesses how well the controls are designed and operating over that duration, providing insights into the reliability and trustworthiness of the service being evaluated.

In contrast, other SOC report subtypes have different focuses. SOC 1 reports are specifically geared towards internal control over financial reporting and can be either Type I, assessing controls at a specific point in time, or Type II. SOC 2 reports, while they also can be Type I or Type II, concentrate on operational controls related to security, availability, processing integrity, confidentiality, or privacy, again with Type II spanning over a period. However, the key distinction is that the Type II designation clearly emphasizes time-based evaluation of ongoing operational effectiveness. SOC 3, on the other hand, is a general-use report which also summarizes the findings of SOC 2 but does not explicitly measure effectiveness over time. Thus, Type II is uniquely centered on the idea of continuous observation and evaluation through a defined timeframe, making it the most suitable answer to the question.