The correct option is A spray comb
The positive terminal of a high tension source (HT) is connected to the
comb B1. Due to the process called action of points, charges are
accumulated at the pointed ends of the comb, the field increases and
ionizes the air near them. The positive charges in air are repelled and
get deposited on the belt due to corona discharge. The charges are
carried by the belt upwards as it moves.