A form of irony that is understood by the audience but not by the characters in a play is

understandable irony.
situational irony.
dramatic irony.
verbal irony.

Dramatic irony

answer C  DRAMATIC IRONY

the direction of the magnetic field produced by an electric current will change when the direction of the electric current changes. for example : if a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).