DropDownList to display values from Two Tables - bold sub heading and normal Text

Hello
I hope I am not asking simple one. 
SUPPORT SERVICES<     Computing Service    Library or Data Engineering    Civil Engineering    Electrical Engineering  I have the data to display in a DropDownList control shown as above. There is a distinct category Type(example Support Services) and Category Name i.e., Computing Services.
I do not want to hard code the values into DropDownList control. I like to get the data from database to display as shown in above Table. Note that Category Type should be displayed in Bold and Category Name in normal Text.
Question:
In order to achieve the above,
1. How many database Tables and relationships betwee ...