The first question is a little strange because an increase in temperature gives an increased density altitude. So if assymetric stall speed varies with one then it has to vary with the other.
As for the second question for a fixed RPM the torque will give you an indication of power:
Power = Torque x RPM.
And for the third I would say the answer could be either again. An anti skid brake system can only be applied to a power brake sytem so answer a. Without power brakes on an a heavy jet one would become VERY tired VERY quickly and so power brakes are needed to 'assist in moving the large quantities of hydraucic fluid required for braking'. And so b is also correct.
At least that is what I remember, the finer points of ATPLs came and went with the exams.