100 g of water is heated from $30^{\circ}C$ to $50^{\circ}C$. Ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is 4148 J/Kg/K) :

Question

( A ) 84 kJ
( B ) 2.1 kJ
( C ) 4.2 kJ
( D ) 8.4 kJ