Which trademark should I protect?
From the information you provided:
You have a brand name
You do not currently have a logo
Having a brand name without a supporting logo is not that unusual. It means that brand name is very important to you is your most important trademark
You should seek to protect your brand name
You can do that by:
Choosing “Word or Words” as they type of trademark you want to protect
Carefully typing in your brand name, making sure you do not include any typos