A plant that needs not less than 10 hours of light to flower is

The correct option is Long day plant.

To understand why this is the correct answer, let's break down how plants respond to the duration of light they receive, a phenomenon known as photoperiodism.
Plants are generally categorized into three main groups based on their photoperiodic responses:

• Short-day plants (SDPs): These plants flower only when the day length (period of light) is shorter than a certain critical duration. They require a longer continuous period of darkness to trigger flowering.
• Long-day plants (LDPs): These plants require a photoperiod that exceeds a certain critical length. In other words, they need a minimum (not less than) number of hours of light (typically 10 to 14 hours) to initiate flowering.
• Day-neutral plants (DNPs): The flowering in these plants is not regulated by the duration of light or darkness they receive; they flower after reaching a certain stage of vegetative growth.

Since the question specifies a plant that needs "not less than 10 hours of light" to flower, it indicates that a minimum threshold of light duration (critical photoperiod) must be met or exceeded. This behavior is characteristic of Long day plants.