Creating a dashboard is the recommended way to meet the requirements of displaying an easy-to-understand visual representation of accounts and opportunities that have been worked on by the sales agents in the current quarter. A dashboard is a collection of components that display data from one or more reports in a graphical format, such as charts, gauges, metrics, and tables. A dashboard allows the user to identify trends, sort data, and measure the impact of their activities. For example, a dashboard could show the number of accounts and opportunities by sales agent, the total amount of closed won opportunities by month, and the average deal size by industry. Creating a list view would not work, because a list view is a filtered set of records that display data in a tabular format, not a graphical format. A list view does not allow the user to identify trends, sort data, or measure the impact of their activities. Creating a custom tab would not work, because a custom tab is a user interface element that allows the user to access a custom object, a web page, or a Lightning page. A custom tab does not display data in a graphical format, but in a record detail or page layout format.