divisional performance

Which one of the following figures would be the most suitable for divisional profit for the purpose of performance measurement?
A Gross profit
B Profit before interest and tax
C Profit before tax
D Profit after tax

– The answer is B
1.Could you explain why the answer is B and not D?
The question asked for the division’s profit(divisional performance) and not the manager’s ‘profit'( managerial performance). Therefore, according to me, tax are traceable costs that relates to the division, therefore should be taken when calculating the division’s profit.

2. Please locate where I am getting things wrong?

Thanks.