Hint: A movement of a plant or plant part in response to a stimulus generated within the plant. Autonomic movements include the beating of cilia and flagella protoplasmic streaming and the movement of chromosomes during the nuclear division.
Complete answer: The opening of floral buds into the flowers, is generally a type of autonomic movement of growth. It is a nastic movement. Nastic movement is basically a non-directional movement displayed by plants in response to external stimuli. The autonomic movement of variation are those movements that occur without the external stimulus, here depending upon the stimulus, they are of two types:
a. Photonastic: - The movements which are induced by the fluctuations in the intensity of light. These types of movements are exhibited by flowers of several plants. Many flowers open with the increasing illumination of the day and close with the decrease in light intensity.
b. Thermonastic: - Here, such types of plants occur due to the temperature. Flowers of these plants open with the rise of temperature and close with the drop in temperature.
Sometimes, Thermonastic movements are also related to photonastic movements. Autonomic movement of locomotion is the movements of the whole plant body or of an organ of material within the plant cell which occur in responses to inherit factors and are free and spontaneous. For example cyclosis, oscillating movements of Oscillatoria, motility of zoospores.
Hence, the correct answer is option (D), i.e., Autonomic movement of growth.
Note: Paratonic movement of growth is defined as the movement of the whole or parts of a plant due to the influence of the stimulus which is external for example, gravity, chemicals, heat, electricity, or light.