For the 'return matrix' heatmap, it's the option A.
At the entry date, the exact options are selected (the expiries and strikes). I look at the price of those options at the entry day, and recheck the prices at the exit dates.
So it's not like in the RV chart where each day the strikes reset.
In the heatmap, when you look at a row, it's always the same option(s). You can check that by looking at the 'individual cycles', and hovering on a cell to see the expiry and strike selected.