Final answer:
An ice cube feels cold due to heat from your hand being transferred via conduction, causing your hand to lose kinetic energy and feel colder. Therefore, the correct option is A.
Step-by-step explanation:
An ice cube feels cold when you hold it because heat from your hand is transferred to the ice cube by a process called conduction. During this transfer, the molecules in your hand lose some of their kinetic energy, which we perceive as heat, to the colder ice cube. This is why option 'c. heat from your hand enters the cube by conduction' is the correct answer. Convection is not involved in this process because it is the movement of heat through fluids (gases or liquids) caused by molecular motion, and it does not occur when holding an ice cube directly in your hand.