The area of hysteresis loop of a material is equivalent to 250 Joule. When 10kg of a material, of density 7.5 gm/cm³, is magnetized by an alternating field of 50Hz, then the energy lost in one hour will be:

• A

  $6\times {10}^{4}J$

• B

  $6\times {10}^{4}erg$

• C

  $3\times {10}^{2}J$

• D

  $3\times {10}^{2}erg$