How can a guest purchase a painting featured in Moonrakers?

The option indicating that a guest can purchase a painting featured in Moonrakers through the restaurant's website is the correct choice because many modern restaurants leverage their online platforms to facilitate transactions. This can enhance the guest's convenience, allowing them to browse available artwork and make purchases directly from the comfort of their home. By integrating art sales into its website, Moonrakers can reach a wider audience and make the purchasing process streamlined and user-friendly.

Using the website for purchases also allows for better management of inventory and ensures that guests have access to the latest offerings without needing to visit the restaurant in person. This method aligns well with contemporary shopping behaviors, where customers prefer online transactions over phone calls or in-person visits for various purchases.

The other options, while potentially viable in different contexts, do not provide the same level of accessibility and ease of use that an online purchase would offer. Thus, the restaurant's website serves as the most efficient and modern approach for guests interested in buying the artwork.