The correct answer is option 3: always upright. The pyramid of energy is a graphical representation of the flow of energy in an ecosystem. It shows the transfer of energy from one trophic level to the next. The pyramid is constructed in such a way that energy flows from the lower levels to the higher levels, resulting in a decrease in energy at each successive trophic level. Therefore, the pyramid is always upright, with the base representing the primary producers (plants), followed by primary consumers, secondary consumers, and so on. The upright shape of the pyramid signifies the decrease in available energy as we move up the food chain. Conversely, an inverted pyramid would indicate an increase in energy from higher to lower trophic levels, which goes against the principles of energy flow.