Generally, for the measurement of the neck, you want to measure between where the shoulders meet the neck and the larynx (or the Adam's Apple) on the neck, which should be between the bottom and the lower middle. It should be the same for both men and women despite how visible the "bump" on the neck is.
In general, you don't want your measurements to be so loose that they do not press into the skin just slightly, but not so tight that it causes discomfort (which is important to remember in this case, as you don't want to strangle anyone!). With all this in mind, I would choose D, "closely around the base of the neck," since it seems to follow my description the closest. I would follow up with a few videos showing how to measure the neck if you have the time!
