A proper catalogue would also show the PR codes for each type:
12 5E0857521 Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors left 1 PR:5SJ,6XD,6XE
12 5E0857521A Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors left 1 PR:5SR,6XD,6XE
12 5E0857521C Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors left 1 PR:5SJ,6XK,6XL
12 5E0857521D Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors left 1 PR:5SR,6XK,6XL
12 5E0857522 Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors right 1 PR:5RQ,6XD,6XE
12 5E0857522A Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors right 1 PR:5RT,6XD,6XE
12 5E0857522C Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors right 1 PR:5RQ,6XK,6XL
12 5E0857522D Mirror glass (convex) with carrier plate
For heated and electric adjustable exterior mirrors right 1 PR:5RT,6XK,6XL
PR code meanings:
PRCode: 5RQ = Right exterior mirror: convex
PRCode: 5RT = Right exterior mirror: convex (AGCC)
PRCode: 5SJ = Left exterior mirror: convex
PRCode: 5SR = Left exterior mirror: convex (AGCC)
PRCode: 6XD = Exterior mirrors: electrically adjustable/heated
PRCode: 6XE = Exterior mirrors: electrically foldable and electrically adjustable/heated
PRCode: 6XK = Exterior mirrors: automatically dimming electrically foldable/adjustable/heated
PRCode: 6XL = Exterior mirrors: with memory function automatically dimming electrically foldable/adjustable/heated
Your picture does look like a auto-dimming type but there are various websites which will decode your VIN to show which PR codes you have and therefore, which you need