Refraction Angle Definitions Steps:

• Identify the incident ray in water approaching the water-air interface.
• Draw the normal perpendicular to the surface at the point of incidence.
• Measure angle i between the incident ray and the normal in water.
• Measure angle r between the refracted ray and the normal in air.

Why A is correct:

• It labels i as the angle between the incident ray in water and the normal, and r as the angle between the refracted ray in air and the normal, matching the standard definition in Snell's law.

Why the others are wrong:

• B: Swaps i and r labels between media.
• C: Measures angles from the surface instead of the normal.
• D: Shows i in air and r in water, reversing the direction.

Final answer: A