Dell Power Manager - Custom Setting

Hello,

I have recently been fiddling with an app called Dell Power Manager, and I have found the different settings e.g., adaptive, standard, etc. Then I came across a setting called Custom - when you can select when the laptop starts and stops charging. What I am curious about is that if I set it to stop charging at, say, 75%, when it reaches 75% for the battery, does it:

A) Use power directly from the charger,

B) Use power from the battery until it reaches say 50% and then start charging again,

C) The rate of power used from the battery is the same rate of power the charger charges the battery.

Please help me understand this. 

Thanks.