Why does the sex cell have fewer chromosomes than a regular cell?

Human sex cells do have 23 chromosomes, but not these 23. Meiosis reduces chromosome number so that sex cells (eggs and sperm) have a half set of chromosomes–one homolog of each pair. This is the haploid number.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

the answer would be b i believe