Hint: Flowering in plants is dependent on several factors including biotic factors and hormonal effect. In modern Sciences, certain hormones are sprayed to plants to make them flower in off-seasons.
In the case of pineapple plants, the Ethylene gas can make it flower in the offseason. This gas is used in fruit ripening as well. It also retards flowering in many plants.
Ethylene, the simplest alkene, is a colorless flammable gas that is used in many chemical industries as plant hormone as well as in the production of polyethylene. This is a hormone that affects the ripening and flowering of various plants. It is also used widely to control freshness in horticulture and fruits.
Additional Information: Zeatin is a cytokinin that is derived from adenine and was discovered in immature corn kernels from the genus Zea. It is responsible for promoting the growth of lateral buds. When sprayed on meristems of plants, it stimulates cell division to produce bushier plants. Zeatin is used mostly to promote callus initiation with auxin, to fruit after blossom, and retardation of yellowing of vegetables. It also causes Auxiliary stems to grow and flower.
Photoperiodism of plants also affects its flowering period. In the case of short-day plants, they flower when the night lengths exceed their critical photoperiod. Some short-day plants are kenaf, marijuana, cotton, rice, green gram, etc.
There are some plants which flowering depends on exposure to temperature and the ones that flower by exposure to low temperature are called vernalization.
So, the correct answer is "(B) Ethylene".
Note: There are certain factors that affect blossoming in plants which are temperature, light, water, and nutrients. Certain hormones like ethylene, auxin, etc also affect flowering to a great extent. Sunlight during summer days also encourages the plant to flower and fruit. According to studies, red light stimulates the flowers to blossom.