The ITER project, a global collaboration aiming to demonstrate nuclear fusion's viability by the mid-2020s, is based on which specific magnetic confinement technology?

1. AA stellarator, which uses a complex, twisted magnetic field.
2. BInertial confinement fusion, using high-powered lasers.
3. CCold fusion, based on electrochemical processes.
4. DA tokamak, which uses a toroidal magnetic field to confine plasma.