OrlandoFL, welcome to the knife wars!
The questions they asked you are to separate a "combat knife" from a "combat zone knife".
There are situations where people at war or at home might use a knife against another person or even an animal. These
combat knives ideally would have a comfortable grip and a sharp blade as long as convenient.
But a soldier not being the most highly paid professional in our society will probably use an issued knife or the kind of inexpensive knife available in the PX. That leaves out your list.
On the other hand, hand to hand combat is a measure of the failure of an operation. Instead of a knife, bring more ammunition. So a
combat zone knife is the kind of knife you need to open packs of food or crates of equipment, to fix broken machinery or prepare food, like butchering animals. Small fixed blade, well-made folder or slip joint, multitool or Swiss Army Knife.