Here metal plate means conducting material so it’s heating effect of current i.e. where I is current, R is resistance and t is time. So options (a) & (d) are correct because either A.C or D.C or induced current, metal plate will get heat.

Also in presence of magnetic field varying with time, there will be induced current called eddy currents and this current heat the metal plate. So option (b) also correct and option (c) is just opposite of option (b) hence option (c) is wrong.

Therefore, options (a), (b) & (d) are the correct.