Step 1: Read what is asked.
We have to find which property of light makes a rainbow. The choices are refraction, dispersion, reflection, or all of these.
Step 2: Picture a rainbow forming.
A rainbow appears after rain because sunlight passes through tiny water drops floating in the air. Each little drop acts like a small glass ball.
Step 3: Light enters the drop (refraction).
When sunlight goes from air into the water drop, it bends. This bending of light is called refraction. So refraction happens first.
Step 4: White light splits into colours (dispersion).
White sunlight is a mix of seven colours. Each colour bends by a slightly different amount, so the colours spread out. This spreading is called dispersion.
Step 5: Light bounces inside (reflection).
The spread colours hit the back wall of the water drop and bounce back. This bouncing inside the drop is internal reflection. The light then refracts once more as it leaves.
Step 6: Put it all together.
So a rainbow uses refraction, then dispersion, then reflection. All three are needed. \[ \boxed{\text{All of these}} \]