Correct option is A
The formula for eddy current loss is:Pe=keBm2f2Where:∙ Pe:Eddy current loss∙ ke:Constant depending on the material and geometry of the core∙ Bm:Maximum flux density∙ f:Frequency of the supplyEddy current loss is directly proportional to the square of thesupply frequency. When a DC source is applied:∙ Frequency (f)=0Substituting f=0 into the equation:Pe=keBm2(0)2=0