For the diagram below, which line represents the heat of reaction Potential energy (KJ)
0 10 20 30 40 50 60 70 80 90
с
b
Reaction coordinate
Line Frepresents the heat of reaction
Line D represents the heat of reaction
Line E represents the heat of reaction
Line A + B represents the heat of reaction

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy

about what?
have a good day

B? i feel like this is a trick  

Ionic compounds dissociate into component ions dissolved into a solution creating substances called "electrolytes".hope my answer has you : )