Answer:
He should ask his sales reps if they believe they can surpass the $500,000 threshold. I doubt their response will be positive.
Explanation:
The sales target is too high. If last year your best sales rep was only able to sell $400,000 in his/her territory, how do you expect him/her and the rest of the sales reps to meet the $500,000 threshold.
If the expectation is set too high, it will be seen as unachievable and wouldn't make any positive effect, it might even cause some negative effects on his employees.