Which combination of conditions produces the highest density altitude, and therefore the greatest reduction in small UA performance?

Why: The Remote Pilot Study Guide states that "the conditions that result in a high density altitude are high elevations, low atmospheric pressures, high temperatures, high humidity, or some combination of these factors," and that as density altitude increases, aircraft performance decreases.

• Describes the opposite combination — the study guide identifies these as the conditions that produce low density altitude and the best performance, not the worst.
• Mixes a high-density-altitude factor (high elevation) with two low-density-altitude factors (high pressure, low temperature), producing a combination the guide does not identify as the worst-case condition.