What does the flux created by the load current in the primary winding, which links only with the primary winding, represent?

The correct answer is option 3.

Leakage flux

• The flux created by the load current in the primary winding, which links only with the primary winding, represents leakage flux.
• This flux doesn't pass through the core to link with the secondary winding and instead, flows through the winding insulation and insulating oil. This leakage flux contributes to the primary leakage reactance. 
• This flux does not contribute to energy transfer between windings and is considered a form of energy loss.

Magnetic flux

• ​Magnetic flux is defined as the number of magnetic field lines passing through a given closed surface. It provides the measurement of the total magnetic field that passes through a given surface area.

Mutual flux

• Mutual flux is the magnetic flux that links both the primary and secondary windings of a transformer, contributing to its operation. 

Induced flux

• Induced flux refers to the change in magnetic flux through a loop of wire, which results in the generation of an electromotive force (EMF) or voltage. This process is a fundamental principle in electromagnetic induction.