Aproton traveling to the right enters a region of uniform magnetic field that points into the screen. when the proton enters this region, it will

deflected toward bottom of the screen
deflected out of the plane of screen
deflected toward top of the screen
deflected into plane of screen
unaffected in its direction of motion

deflected toward top of the screen

Explanation:

We can find the direction of the force acting on the proton by using the right-hand rule. In fact, we have:

- Index finger: direction of motion of the proton --> to the right

- Middle finger: direction of the magnetic field --> into the screen

- Thumb: it gives the direction of the force --> therefore, it will be upward

And since the charge is positive (it is a proton), we don't have to revers the direction: so, the force on the proton points upward.

Therefore, the correct answer will be

deflected toward top of the screen