Final answer:
The correct answer to the question is c) 'One system must have higher kinetic energy than the other system,' as heat conduction requires a temperature difference between the systems to initiate the transfer of thermal energy.
Step-by-step explanation:
Heat conduction is the transfer of thermal energy between two objects that are in direct physical contact. For heat to flow through conduction, there must be a temperature difference between the two systems. Specifically, one system must have a higher kinetic energy than the other, which is associated with a higher temperature. Therefore, heat will flow from the system with higher kinetic energy (and temperature) to the system with lower kinetic energy (and temperature), until thermal equilibrium is reached.
Option c) 'One system must have higher kinetic energy than the other system' is the correct answer to the question posed by the student. This kinetic energy difference is what drives the flow of heat from the hotter object to the cooler one, as described by the second law of thermodynamics. The objects in thermal contact will thus continue to experience heat transfer until they are at the same temperature.