For a current carrying conductor,which of the following is/are true ?

A)Electrons are current carriers

B)Positive charges are current carriers

C)Field is uniform

D)Field is non uniform

A and C.

In metals, which make up the wires and other conductors in most electrical circuits, the positive charges are immobile, and the charge carriers are electrons. Because the electron carries negative charge, the electron motion in a metal conductor is in the direction opposite to that of conventional (electric) current.

As we consider ideal cases in electrical circuits therefore field is uniform.

A) and C0 are correct