Final answer:
We do not power ocean liners or airplanes by extracting heat from oceans or the atmosphere due to the impractically low efficiency of such a process and the unsuitably cold temperatures for traditional heat engine operation. High costs and potential environmental impacts further hinder the feasibility of these technologies. Therefore, correct option is c.
Step-by-step explanation:
The primary reason we don't operate ocean liners by extracting heat from the ocean or operate airplanes by extracting heat from the atmosphere can primarily boil down to inefficiency (c).
The technology essentially relies on heat engines that operate on a temperature difference, and in many cases, the available temperature difference between the heat source (the ocean or atmosphere) and the heat sink (environment) is too small.
This results in an impractically low efficiency, making it unsuitable for powering ocean liners or airplanes which require a significant amount of energy to operate. As the ocean's heat content is not high, any attempted ocean thermal energy conversion would suffer from low efficiency.
Additionally, there are high logistical challenges and costs associated with deploying and maintaining large installations at sea and transmitting power back to land.
Despite ocean thermal energy being a vast resource because of the huge surface area of the ocean that can act as a solar collector, it does not generate enough heat to be practical for power generation on a scale necessary for ocean liners.
Moreover, such low-efficiency systems would not be suitable for powering airplanes, which operate in an environment where temperatures can be below the freezing point of water, thwarting the operations of a traditional steam engine (b).
Environmental concerns and high costs are also contributory factors that prevent these technologies from being feasible. Continuous extraction of heat could also have unintended environmental impacts.
The financial outlay for developing non-fossil energy infrastructure on the required scale is significant and may not be viable given current economic conditions (d).