What are the permalinks options for “Category” base and removing it?

there is an answer to on how to do that in the WordPress way here

but a faster way is using the .htaccess file by adding this line

RewriteRule ^category/(.+)$ http://www.yourblog.com/$1 [R=301,L]

just make sure you change http://www.yourblog.com/ to what ever is needed.

Hope this helps.