A certain species of frog has a diploid chromosome number of 2n=262n = 262n=26. During spermatogenesis in a male, complete non-disjunction of all chromosomes occurs during meiosis I, whilst meiosis II proceeds normally as shown in the diagram below.
If one of these diploid sperm fertilises a normal, haploid egg from a female of the same species, what will be the chromosome number and ploidy of the resulting zygote?
393939 chromosomes, triploid (3n3n3n)
272727 chromosomes, trisomic (2n+12n+12n+1)
525252 chromosomes, tetraploid (4n4n4n)
262626 chromosomes, diploid (2n2n2n)