( A ) $ \Delta H_{Soln} = \Delta H_1 - \Delta H_2 - \Delta H_3$
( B ) $ \Delta H_{Soln} = \Delta H_3 - \Delta H_1 - \Delta H_2$
( C ) $ \Delta H_{Soln} = \Delta H_1 + \Delta H_2 + \Delta H_3$
( D ) $ \Delta H_{Soln} = \Delta H_1 + \Delta H_2 - \Delta H_3$