We can solve this using right-hand rules! :)
Going into chamber 1, the velocity points down and the centripetal force points to the right, so the magnetic field points: into the page.
For chamber 2, the velocity points to the right and force points down, so the magnetic field points: out of the page.
Going into chamber 3, velocity points down and force is to the left, so the magnetic field is: out of the page.
And for chamber 4, velocity points left and force points down so the magnetic field points: into the page!
Hope this makes sense and helps :)
