Explanation: An oscilloscope displays the instantaneous voltage of a signal over time. When viewing a pure sine wave, the highest positive voltage point (peak) and the lowest negative voltage point (trough) are the most visually distinct and easily identifiable features on the screen. The peak-to-peak voltage is simply the total vertical distance between these two readily observable extremes. RMS (Root Mean Square) voltage is an effective value related to power dissipation and requires calculation, not direct visual measurement. For a pure sine wave, the average voltage over a complete cycle is zero, making it unsuitable for measuring amplitude. DC refers to a constant voltage, which, while it can be a component of a signal, is not the amplitude of the alternating sine wave itself. Therefore, peak-to-peak is the most straightforward and direct amplitude measurement from an oscilloscope display.