The correct options are
C Their blood starts to clot.
D Their body becomes colder.
When a person is met with an electric shock, their body temperature decreases hence they get colder by every minute. Because of this, their blood temperature falls down thereby it gets more viscous(thick). As the blood starts to thicken up, the clotting begins. Also the blood supply to the body muscles decreases thereby contracting or tightening up the muscles.
If left untreated, the victim may even die of heart failure which is why it is always important to be very cautious when dealing with electrical equipment.