Right-hand rule determines magnetic field direction around a current-carrying wire

Steps:

• Identify the direction of current in the wire.
• Point thumb of right hand in direction of current flow.
• Curl fingers to show circular path of magnetic field lines around wire.
• At the marked point, field direction is tangent to the circle, following finger curl.

Why D is correct:

• Arrow D aligns with the right-hand rule, pointing in the tangential direction of the field circle.

Why the others are wrong:

• A points radially outward, opposite to field lines.
• B points opposite the curl direction.
• C points into the wire, not tangential.

Final answer: D