the current is pass through the straight wire. The magnetic field established around it has its lines of force:
Circular and endless
Oval in shape and endless
Straight
Parabolic
Electrons
Positive ions
Negative ions
Both (A) and (C)
Both (A) and (B)
In order to have a constant current through wire, the potential difference across its end should:
Be zero
Be maintained constant
Goes on increasing
Go on decreasing