What you need to remember is that the only cells that are haploid are the gametes; the sperm and the egg. Haploid means they have half the number of chromosomes: 23.
A points to formation of the gametes. Meiosis is the answer because it produces the gametes.
B points to the haploid egg cell. The answer is haploid. C, N=23.
D points to haploid sperm cell. Answer is haploid. E, N=23.
F shows the sperm meeting the egg. That is fertilization.
G The sperm and egg fuse to form zygote. They combine their chromosome numbers to form a full diploid cell.
H Now that the zygote is diploid it has all 46 chromosomes.
I points to zygote cell replicating to form copies of similar cells. That is mitosis.
J is showing a diploid embyro.
K 2N =46
L Your normal body cells (somatic cells) are all diploid. Therefore the adults are made up of mostly diploid cells. Answer is diploid.
M 2N= 46.