The greatest number of anode heat units for a single exposur…

The greatest number of anode heat units for a single exposure will be produced by which of the following set of factors: option mA time kVp rectification 1. 100 0.15 sec 85 single phase full wave 2. 300 0.075 sec 92 single phase full wave 3. 600 0.015 sec 89 3 phase  4. 300 0.06 sec 70 3 phase            .