When the dark period of short day plants is interrupted by a brief exposure of light, then the plant

The correct answer is will not flower at all.

Photoperiodism is the physiological response of plants to the relative lengths of light (day) and dark (night) periods. Plants are classified into different categories based on their photoperiodic requirements for flowering, such as short-day plants (SDPs) and long-day plants (LDPs).
For short-day plants, the length of the continuous dark period (night) is the critical factor determining whether they will flower. These plants require a continuous, uninterrupted dark period that exceeds a specific critical length in order to initiate the flowering process.

If this critical dark period is interrupted, even briefly, by exposure to light (often referred to as a "night break" or light flash), the plant's internal biological clock is reset. The plant perceives this interruption as two shorter dark periods instead of one continuous long dark period.
Because neither of the resulting shorter dark periods meets the minimum critical duration required for flowering, the biochemical signals (such as the hormone florigen) necessary to initiate flowering are not produced. Consequently, the short-day plant will remain vegetative and will not flower at all.