Which equation represents the polar form of x minus y is equal to 0 ?

In polar coordinates, x = r cos θ and y = r sin θ. The equation x − y = 0 means x = y, so cos θ = sin θ and tan θ = 1. This gives θ = π/4 (modulo π), so the matching choice is θ = π/4.

AI-written and checked against the verified answer.