Are all options loaded to memory on each request?
Yes, sort of. When the get_option call is made, WordPress runs a function called wp_load_alloptions, which either grabs a cached copy of all autoloaded options or loads all those options into the cache. Then wp_load_alloptions returns an array of all the autoloaded options. If your option is autoloaded (specified when you use the add_option function), … Read more