Because your main commodity is socks, and socks belong to the 2509 similar group of 25 categories, so 25 categories should belong to the core category that needs trademark registration.
If you have registered the 25th category and further wish to register your trademark in the 35th category-advertising sales, because the 35th category is like the following 9 similar groups:
In order to fully protect your trademark, it is recommended to register a service item in each of the above nine similar groups.
If you have any other questions, you can consult further.