What type of scripts can be used with HTTP monitors for pre- and post-execution?

The correct choice is custom JavaScript, as it allows you to create flexible and powerful pre- and post-execution scripts within HTTP monitors. JavaScript enables you to manipulate requests and responses dynamically, giving you control to customize behaviors such as validating responses, modifying headers, or extracting data for assertions.

In the context of HTTP monitors, JavaScript is particularly suitable because it is natively supported in most web environments and can run quickly in response to HTTP requests. This makes it an effective tool for handling various scenarios that a web application might encounter during performance monitoring.

Other options like HTML scripts and CSS stylesheets are not applicable in this context, as they are primarily intended for structuring and styling web content rather than facilitating programmatic logic for monitoring. Python scripts, while powerful in their own right, may not be supported in the same way as JavaScript within some monitoring platforms, thus limiting their utility for this specific purpose.