I need help with the following question about electromagnetism.

In the figure on the right, a conductor ring with radius r, is placed inside a solenoid with radius r2. Treat the solenoid as infinitely long, with tightly wound turns of N turns per L length. The current in the solenoid is slowly varying as I = Io sin wt. a) Find the magnetic field in the solenoid. b) Find the induced emf in the conductor ring. c) If the resistance of the conductor ring is Ro, find the induced magnetic field at the center of the conductor ring. (Hint: this field is created by the induced current.) d) At t = 0, check if your result in part-c agrees with Lenz's law