Final answer:
A high cart abandonment rate is a sign that customers are having trouble with a device when making purchases, suggesting issues with user experience during the checkout process.
Step-by-step explanation:
The sign that customers are having trouble using a particular device to purchase the options provided is d) High cart abandonment rate. This metric indicates the percentage of shoppers who add items to their cart but do not complete the purchase process. A high cart abandonment rate can be due to various issues such as complicated navigation, unexpected costs, or a lengthy checkout process, all of which can frustrate users and dissuade them from completing their transactions. Conversely, increased website traffic indicates more visitors, a low bounce rate suggests that users find the site relevant and are engaging with it, and a high conversion rate means a greater proportion of visitors are making purchases.