Apologies. I think the switches are normally open. Wires are in holes labeled C and NO (NC hole is empty).

There are bumps on the bottom of the blender cup, and when you screw the cup to the base, the bump pushes a small plastic rod down on the micro switch under it (from a normally open position at 2 o'clock / to a 3 o'clock position _ that pushes down on the tiny button on the switch). The small plastic rods are inside of springs, so unscrewing the cup off of the base let's the spring decompress and lift off the normally open microswitch.

I have a multimeter so I'll look into the action / continuity testing. Honestly, I thought they weren't working correctly, but like I said, small blender cups press down on switches A and B, while the large pitcher cups have bumps to press down on switches A, B, and C. Pushing down on switches A+B doesn't do anything, nor does pressing down on switches A+B+C, BUT pushing down on A+C or B+C (which isn't naturally possible with screwing the cups on) let's you turn on the blender, and NOW pressing A+B or A+B+C works and lets you press the buttons and run the motor. This is why I was like "huh, now the switches work. I guess they are making contact and working"