Answer: Your (false) assumption that Vlad is an athlete is most clearly an example of the representativeness heuristic
Step-by-step explanation:
The representativeness heuristic is a short cut that we take to come to a conclusion or decision when we don't have sufficient information about something or someone by using what we already know.
The fact that we know what the gym is associated with , we will retrieve that information that already exist in our mind and link it with this new situation that we are trying to resolve in our mind.
Gym is associated with exercising and that information is what we have hence we will use that to assume that this person exercises because they go to the gym everyday.