Answer:
D) Both haploid and diploid multicellular organisms.
Explanation:
Alternation of generations,a reproductive cycle of certain vascular
plants, fungi, and protists can be defined as the alternation of
multicellular diploid and haploid forms in the organism's life cycle,
regardless of whether or not these forms are free-living.
All plants undergo a life cycle that takes them through both haploid
and diploid generations. The multicellular diploid plant structure is
called the sporophyte, which produces spores through meiotic
(asexual) division. The multicellular haploid plant structure is called
the gametophyte, which is formed from the spore and give rise to the
haploid gametes.
The fluctuation between these diploid and haploid
stages that occurs in plants is called the alternation of generations.
