Correct option is (iv) Primary coil is made up of a very thick copper wire.
Explanation:
Correct statement is option (iv) as Primary coil made of Thick Coper wire has very less R. Therefore negligible power loss. Rest all options are reasons for power losses in a transformer.
Power loss happens due to Eddy current, Flux loss and Hysteresis. But in a transformer, the primary coil is made up of a very thick copper which has very less resistance and therefore negligible power loss due to heat.