Correct Answer: D
https://developer.servicenow.com/dev.do#!/learn/learning-plans/rome/new_to_servicenow/app_store_learnv2_scripting_rome_debugging_client_scripts The following are debugging strategies for client-side scripts, which run in the web browser and manipulate the user interface:
g_form.addInfoMessage(). This is a client-side API that displays an information message at the top of the form.
Field Watcher. This is a debugging tool that displays the current and previous values of one or more fields on a form.
jslog(). This is a client-side API that writes a message to the browser console.
The following is not a debugging strategy for client-side scripts, but for server-side scripts, which run on the ServiceNow platform and manipulate the database:
gs.log(). This is a server-side API that writes a message to the system log. Reference: Client-Side Scripting APIs, Debugging Client Scripts