AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
(C) Concentric circles centred on the conductor
The field lines about a current-carrying straight wire consist of a series of concentric circles whose direction is given by the right-hand thumb rule.
The textbook explicitly states in the summary: "The field lines about the wire consist of a series of concentric circles whose direction is given by the right-hand rule." Examiners expect the correct option letter AND a brief justification for MCQs. Avoid confusing this with a circular coil (where field lines at the centre appear as straight lines).