GST implication on sale of used Vehicle

Dear Experts,

a- What is the GST implication on sale of used vehicle if ITC not claimed if it is sold for a margin?

b- For calculating margin, which WDV to be taken (ie; WDV as per IT act or as per Companies act)

c- also which date of WDV to be considered, WDV as on date of supply or WDV at the end of relevant fina year?