The correct answer is: D. No matter what the circumstances, individuals choice always involve a trade-off
This is because economics is the study of how people make choices under conditions of scarcity. Scarcity means that there are not enough resources to satisfy all of our wants. As a result, we have to make choices about how to allocate our resources. Every choice we make involves giving up something else. For example, if we choose to spend our money on a new car, we are giving up the opportunity to spend that money on something else, such as a vacation.
The other options are also important concepts in economics, but they are not the fundamental premise of economics. Option A is the idea of rationality, which is the idea that people make choices that are in their best interests. Option B is the idea of scarcity, which is the idea that there are not enough resources to satisfy all of our wants. Option C is the idea of marginalism, which is the idea that we make choices by comparing the marginal benefits and marginal costs of different options.
However, all of these concepts are based on the idea that individuals have to make choices under conditions of scarcity. As a result, the fundamental premise of economics is that individuals choice always involve a trade-off.