I'm interpreting (B) to have on the left a san-tee on its back with the side inlet upright (or possibly rolled a little to bypass the WC vertical drain). That's never allowed for drainage, you'd do it with a wye and a 45 instead of a san-tee and a 90. But even that is not considered a proper wet vent.
Here's a 4th option (D) that is definitely good: it's like (B) but the two fittings on the left are a wye and a 45, flat (2% slope), so the center line of the horizontal lav drain and the centerline of the horizontal WC drain are at the same elevation. The lav san-tee and the closet ring are ideally offset in the dimension out of the page, and the wye can be in either configuration, so that the combined horizontal 3" line is in line with the lav drain or with the WC drain.
I believe option (A) is okay, but some say the toilet has to join the horizontal wet vented drain on the horizontal, not the vertical like that, hence option (D). I don't find any code language to support that, but I don't have the experience to say whether it will make a performance difference.
So if your trench is wide enough and the layout works, go with (D). Otherwise, option (A) is better than option (C).
Cheers, Wayne