Harvesting cut flowers at the correct stage is essential for maximizing their vase life and quality. Roses are typically cut when they are in the \textit{tight bud stage}. This is characterized by closed petals that have achieved full color development. Harvesting at this stage allows the rose to continue opening naturally once in the vase, thus extending its longevity. (A) Carnation – Incorrect. Carnations are generally harvested at the half-open stage. (B) Jasmine – Incorrect. Jasmine flowers are frequently harvested when fully open. (C) Rose – Correct. Harvested at the tight bud stage for optimal longevity. (D) Gladiolus – Incorrect. Gladiolus is harvested at spike emergence or early flowering.