Multiple choice
Execute the circuit and measure. How likely is the outcome |1⟩?
// theta = 2*pi/3 gives cos(pi/3)=1/2 on |0> and sin(pi/3)=sqrt(3)/2 on |1>. const c = circuit(1); c.ry((2 * Math.PI) / 3, 0); return c;
Commit your prediction for P(|1⟩) — then run it.