The answer in the course is 1 at the question "How many VCPUs do you have remaining ?"
I don't know if my lab instance is different, but I have 4 VCPU in the hypervisor, and 1 used by the instance, so, the answer should be 3
There could have been a change in the alloted vCPUs. The important take away is to know where to find the current used and available CPU usage. As well its important to notice that non-admin projects view the quota not the actual amount of CPUs available. It looks like you have both those points well in hand.
I'll investigate if the vCPUs have changed.