Kingsgate Dental Practice, Winchester. Every mark is hand-authored SVG on a 64-unit grid. Healthcare marks are conventionally symmetrical and clean-lined — that convention is kept — and the subject is the quadrant: dentists chart a mouth as four quadrants, upper right, upper left, lower left, lower right, numbered 1 to 4. Nothing here is clip-art and nothing is a font-only wordmark.
Round 1 verdict — A. B is the cliché and is here to be rejected: every third dental logo is an outline molar, and by 24px it is an indistinct blob. D confirmed the borrowed convention does not transfer — a letter in a rounded square reads as a phone app, and says nothing about the trade. C was closest to A but rounding every corner of every tile makes it a generic grid icon, and the 32%-opacity tiles go weak and grey. A wins for one specific reason: cutting the cross out of a single rounded square leaves each quadrant with a rounded outer corner and a square inner one — which is the shape of a dental arch segment, and is why it reads as a charted mouth rather than as four boxes. Round 2 pushes that asymmetry.