how to buy a routeros lvl4 key?

RouterOS Beginner Basics
1

i am using my own computer do routeros..
and i need a lvl4 key..
when i try to buy lvl4 key from internet…
it ask if my system is x86 system /router board 230 or RouterBoard
..what should i choose? what does that mean?
plz help

2

well what DO you have ? where will you install RouterOS ? On a PC or on a RouterBOARD? Probably a PC, then choose X86