Please help me with the following question, answer and show the work you did to get to the solution, thank you i need help with this asap.
In a device called a velocity selector negatively charged particles are moving through a region of space with both an electric field and a magnetic field. If the speed of the has a particular value, the net force acting on it is 0. Assume that a negatively charged particle moves in the positive X-direction and that the electric field is in positive y-direction. In which direction has the magnetic field to be in order to give a 0 net force?
A- positive y
B- positive z
C- negative y
D- negative z