Answer:
The correct answer is D: diploid phase
Step-by-step explanation:
The essence of plant life is their characteristic property of alternation of generations. Each plant undergoes alternation of generations and produces haploid and diploid generations.
This property allows the plant to reproduce both sexually and asexually. Primitive plant species used to reproduce through spores and spent the majority of their life as haploid cells. These cells were called as spores and required only matter and energy to reproduce.
Modern plant species reproduce by using gametes and spent the majority of their life in diploid phase called diploid sporophytes.