ANS:C - causes heat loss due to poor heat transfer.

When frost forms on the evaporator tubes in a refrigerator, it acts as an insulating layer, hindering the transfer of heat between the refrigerant in the tubes and the items stored in the refrigerator. This insulation effect reduces the efficiency of the heat transfer process, as the refrigerant cannot effectively absorb heat from the refrigerator's interior. As a result, the compressor needs to work harder and run for longer periods to maintain the desired temperature inside the refrigerator. This increased workload on the compressor leads to higher energy consumption, as it requires more power to remove the same amount of heat from the interior. Therefore, frost formation causing poor heat transfer can indirectly lead to heat loss inside the refrigerator due to the increased energy consumption required to compensate for the reduced efficiency of the cooling process.