In the above image, I have a drop-down where values are grouped. When I select the value from the list then drop down should display values as c1 or c2?
It depends on the content. Here are some considerations:
- group name is only a visual clue to find a value easier, and the group is commonly known by the users --> don't show the group name
- group name is essential to understand the value (e.g. two identical values that can be used differently cars > golf or sports > golf) you defenitly need to show both
- group names are not commonly known by the users --> you should consider not to group the values because there is not additional help to the user
If the top level category still bears importance then I'd go for C1. Similar to a breadcrumb on an ecommerce site. Some users may prefer this option as it provides a little more information.
If the drop down is simply to pick a single item to carry onto the next step of the journey then C2 should be fine.
As per the website, I have gone through I found out they do not show the main group heading.