It has been posted in several places that Tactical Critical Chance is capped at 15%.

The description of the Minstrel trait called "Unrelenting" says that Piercing Cry gains 25% to its critical chance.

The question I have is what the effect actually does.
If your critical chance was already 14% and you equip the trait what is the result?
a) 14% + 25% = 39%
b) 14% * 1.25 = 17.5%
c) 14% * 1.25 = 17.5% but reduced to 15%