Which type of system would best allow customers to see real-time statistics on their banner ads?

The correct choice, which is the extranet, fundamentally refers to a private network that allows authorized external users, such as customers and partners, to access certain information from an organization’s internal systems. This capability is essential for providing real-time statistics on banner ads.

An extranet would facilitate direct interaction between the organization and its customers, enabling customers to log in and access up-to-the-minute analytics and performance data related to their advertising efforts. This level of access is critical for customers who need to adjust their marketing strategies based on the real-time performance of their ads.

The other options, while valuable in different contexts, do not provide the same level of external access that is necessary for customers to view their statistics. A Customer Relationship Management (CRM) system typically focuses on managing a company's interactions with current and potential customers and is more about internal organization processes than customer-facing statistics. An enterprise system encompasses various integrated applications to manage business functions but is usually used for internal purposes rather than direct customer access. An intranet, being a private network for a single organization, restricts access to internal users only, thus preventing customers from viewing real-time data on ads.