Yes. Sorry. It’s an A180d. My mistake.I'm sorry you have me confused now...
You said you "just bought a used A100d", and under your username it lists "A100d 2017"
I questioned this never having heard of an A100d but gave options for what it might be - A180d or A200d.
So i can only assume you have made a mistake in typing A100d twice.
I have no idea why the Start/Stop button has an A on it, but it seems to be like this on many cars.
All i can think of is the A stands for Auto (start/stop).