I'm just going to give my two cents worth on this one, but as I know performance pay is when an individual's WAGE/SALARY is matched according to his/her performance in the regards to the business' goals. With Sally, her group is being rewarded for meeting their sales target. It seems to me (because the question is so vague) that the payment is a one-off thing, when performance pay is as a whole IMHO (e.g. If a cars salesman sells 20 units of cars, there's a 20% increase in his wage, so forth...). I'll reiterate, in Sally's case, it seems there's only a cash bonus involved.
On the other hand, Jamie is continuously being rewarded with 5% increase. It didn't say anything about being competitive or whatnot in the question... just for some reason, Jaime is being rewarded continuously with a higher rate of pay. So, a business wouldn't just increase pay for an individual unless certain skills are involved. Furthermore, I guess it's just that it was individual... aka performance pay is linked to individual performance... not group. IDK.
I might've gotten this question wrong but it's okay haha