A stationary positive charge, q, is located in a magnetic field, b, which is directed toward the right. what is the direction of the magnetic force on q?

There is no magnetic force on the charge. Magnetic force will only be on the charge when the charge is in motion. Because, mangetic forec, F = q (v*B)

where v = velocity of charge particle.

B is magnetic field

v is the velocity of charge.

Since the velocity of charge is zero, Thus, F will be zero. So, there is no magnetic force.