The correct option is
D Reproduction growth
Photoperiodism is any response of a plant to the relative lengths
of daylight and darkness. Initiation of flowering at the shoot apical meristem is one of several physiological activities that are photoperiodic in many plants. Plants are classified into four main groups- short-day, long-day, intermediate-day, and day neutral, on the basis of how photoperiodism affects their transition from vegetative growth to flowering.
Thus, the correct answer is option D.