A steady current I flows along an infinitely long hollow cylindrical conductor of radius R. This cylinder is placed coaxially inside an infinite solenoid of radius 2R. The solenoid has n turns per unit length and carries a steady current I. Consider a point P at a distance r from the common axis. The correct statement(s) is (are)

A

In the region 0 < r < R, the magnetic field is non-zero.

B

In the region R < r < 2R, the magneticfield is along the common axis.

C

In the region R < r < 2R, the magnetic field is tangential to the circle of radiusr, centered on the axis.

D

In the region r > 2R, the magnetic field is non-zero.