Question

at which position are red giants plotted?

Explanation:

Step1: Recall Red Giant Properties

Red giants are cool (low temperature, ~3000 - 5000 K) and luminous (high brightness). On the Hertzsprung - Russell (HR) diagram (luminosity vs temperature), they lie in the upper - right (low temp, high luminosity) or check the plot's regions.

Step2: Analyze the Plot Regions

Looking at the plot: Region C (or the labeled C) corresponds to the area where red giants (cool, luminous) are plotted. Comparing with the HR diagram structure, red giants are in the region with lower temperature (left - side of main sequence, upper right in some axes) and high luminosity. The position labeled C matches the red giant's location (cooler than main sequence stars in the AB region, more luminous than the lower - right regions like D/B, and less hot than E which is very hot (O/B type maybe)).

Answer:

C (the position labeled C on the blue - colored options, corresponding to the red giant region on the HR - like plot)