The capacity of a transformer can be increased by:
1. submerging the core and windings in a tank of oil
2. submerging the core and windings in a tank of water
3. forced air cooling the oil in a heat exchanger
4. wrapping the core with a thermal insulation
5. forced air cooling of the core
a) 1, 3, 5
b) 2, 3, 4
c) 1, 4, 5
d) 2, 3, 4, 5
e) 2, 4, 5
Answer: A