Final answer:
In a template, you should define Fields, Field sections, Icon, and parent templates. These elements help in structuring the template, visual identification, organization, and establishing hierarchies for template inheritance.
Step-by-step explanation:
When defining a template, one should consider various components that determine its functionality and how it will interface with other templates or documents. The correct answer to what you should define in a template is Fields, Field sections, Icon and parent templates (A).
Templates typically contain fields, which are placeholders for data that can be filled in dynamically. Field sections are groups of fields that are related, making it easier to organize and manage the data within the template. An icon is often associated with the template to provide a visual representation, making it easier to identify among other templates. Finally, parent templates are templates that can act as a base or starting point for creating other related templates, often known as child templates.
By defining these components in a template, you ensure that it is not only properly structured but also that it integrates well with other templates and systems as necessary, improving usability and maintainability.