Magnetic lines form continuous closed loop. Why ?

(A) : Magnetic lines forms closed loops in nature. (R) : Mono-magnetic pole does not exist in nature.

Magnetic field lines are

(A) : Ampere's law holds for steady currents in straight conductor which do not vary with time. (R) : Magnetic field lines always form closed loops.

Harsha told that Magnetic field lines are closed loops. But Krishna is not agreeing with Harsha. How Harsha will convince Krishna with an experiment ? What are the apparatus required ? How the experiment will be conducted ?

Electrostatic field lines of force do not form closed loops. If they form closed loops then the work done in moving a charge along a closed path will be zero. From the above two statements can you guess the nature of electrostatic force?

How can you verify with experiment."The magnetic field lines are closed loops"?