Of course there are various versions of NPCs, some stand and do nothing, others are more complex, they often "adapt" to certain conditions. For example, if an NPC is following the player it might "decide" to switch to running if the distance to the player reaches a certain threshold, decide how to navigate around other dynamic/moving NPCs, etc. In this example, the NPC "acquires" knowledge by polling the distance to the player and applies that "knowledge" by using its internal model to make a decision to walk or run.
The term "acquiring knowledge" is pretty much as subjective as "intelligence". In the case of an ant, for example, it can't really learn anything, at best it has a tiny short-term memory in which it keeps certain most recent decisions, but it surely gets things done, like building colonies.
For both cases, it's just a line in the sand.
In a way, yes, if you frame it right. To simplify, you're basically asking "is a calculator intelligent?", right? While it's an inanimate object, you could say that, in a way, it acquires knowledge from the buttons user presses and it applies knowledge to provide an output.
"But that's not making decisions, it's just circuits!", you might say. To which I might reply "Who's to say that you're making decisions? For all we know, human brains might also just be very complicated circuits with no agency at all, just like the calculator!".
IIRC, in his book The Singularity Is Near, Ray Kurzweil even assigns certain amount of intelligence to inanimate objects, such as rocks. A very low amount of course, and it might be a stretch, but still.
So yeah, it's really hard to draw a line for intelligence, which is why there's no firm definition and no consensus.