The correct answer is: d all sex cells having 23 chromosomes.
During meiosis, the process of gamete formation in humans (and most organisms), the number of chromosomes is halved. Humans have a diploid number of 46 chromosomes, which consists of 23 pairs. Meiosis results in gametes (sex cells) that each have 23 individual chromosomes (haploid), which is why option d is the correct choice.