How do I make collisions with tilemaps?

I feel like I've done it before, and I feel like someone's probably asked before but because constructs search is a roll of the dice, here's my question.

How do I collide with tile A, but not the other tiles?

I read the documentation on it but I still couldn't figure it out. Disabling collisions would still have collisions anyway, and removing solid but leaving collisions would not have collisions.