Answer is the first option Place a metal paper clip on a table and slowly bring each electromagnet closer to the paper clip to see which can attract the paper clip from a greater distance.
I don't know why but I find your questions a bit too easy..
A) heat from the sun hope this helped
DDT was used during second world war to control malaria among the troops and the civilians. Later, it was used as pesticide in agricultural and household practices. Due to its excessive use it entered into the food chain and its amount in the food crossed the permissible level. So, it was banned by United States.