you see Amazon was the biggest U$.$S$.$ advertiser in $2021,$ spending $$10\mathrm{.}4$ billion $($up from $$6\mathrm{.}8$ billion in $2020).$ Do you think this expense is justified? How has it helped or hurt their profits? Do some research on Amazon's use of other elements of the promotion mix on slide $26($sales promotion, personal selling, and public relations$)$ and explain why they have or have not been successful.