The cheapest and oldest freezing technique is brine freezing, making choice (C) Brine freezingthe perfect answer. Brine freezing includes the usage of a combination of water and salt (brine) to freeze food or different substances. This method has been used historically because of its simplicity and value-effectiveness, particularly earlier than the advent of greater superior freezing technology. It is particularly straightforward and cheaper compared to other methods like flash freezing or immersion freezing.