The correct options are
B Avoid bathing.
C Take shelter under shorter trees.
During a thunderstorm, contact with telephone cords, electrical wires and metal pipes should be avoided. Bathing should be avoided during thunderstorms to avoid contact with running water. Carrying an umbrella with a metal cap is not a good idea at all during thunderstorms. If in a forest, it is comparatively safer to take shelter under shorter trees. If no shelter is available and in an open field, it is advisable to stay far away from all trees.