Question

which section of the diagram includes the coolest, brightest stars? section 1 section 2 section 3 section 4

Explanation:

In an H - R diagram (which this appears to be), cooler stars have lower temperatures and are on the right - hand side of the temperature axis, and brighter stars have higher luminosities and are towards the top of the luminosity axis. Section 1 is in the upper right where temperatures are low (cool) and luminosities are high (bright).

Answer:

A. Section 1