The correct options are
B Free-electron density
D The charge crossing in a given time interval
We know, drift velocity and current density both are inversely proportional to the cross sectional area of the conductor. Here, the cross sectional area of the given conductor is non-uniform hence, both the quantities changes with change in cross sectional area of the conductor.
Also, current through the conductor in independent of the cross sectional area of the conductor hence, the charge crossing in a given time interval and free-electron density both are independent of cross sectional area of the conductor.