Good question.
Quote:
6.1.6 Set-up Remaining Formations
All of the remaining formations in the players’ armies must be set up within 15cms of their own side’s table edge or be kept back ‘in reserve’.
When I first read it, I thought that 'Read as Written' (RAW) the answer would be option A: the player's table edge is 60cm of the short edge and 90cm of the long edge, so they can deploy within 15cm of those edges.
That would allow them to have a unit 75cm up the short edge or 105cm down the long edge, as shown by the extra space given by measuring the curves on the end of the deployment area, as shown in Option A.
However, this isn't actually correct, because "All of the remaining formations in the players’ armies must be set up within 15cms of their own side’s table edge" specifically refers to the table edge, and the deployment rules in 6.1.2 distinguish between the edge and the corner.
Quote:
6.1.2 You can pick a long edge, or a corner (half way up each long and short edge). The opponent sets up on the opposite edge or corner.
In conclusion, as far as I can tell there isn't a hidden easter-egg in the rules that allows that extra stretch of 15cm when deploying in Corners. The wording distingishes between Edge and Corner deployment, so using the 'set up within 15cms of their own side’s table edge' to gain an advantage in Corner deployment wouldn't be correct.
(BTW if there is an FAQ needed, it would be to clarify exactly how formations deploy when it is a Corner deployment).