Answer:
The correct answer is option 3, that is, will not be affected by either pole of a magnet.
Step-by-step explanation:
Beta particles refer to the electrons that comprise negative charge. The charge is not influenced by magnets, until and unless it is motion. If it is motion, then its electric current encounters with a force away or towards the magnets. In the question it is not mentioned that the beta particles are in motion, thus, we have to presume that they are just lying there, and thus beta particles will not be affected by either of the poles of a magnet.