Subway, with more than $3,000$ outlets in Canada, is planning for a new restaurant in Brampton, Ontario. Three locations are being considered. The following table gives the factors for each site:

$\backslash$table$[[$Factors$,,$Location A$,$Location B$,$La$],[$Space$,0\mathrm{.}30,60,70,80],[$Costs$,0\mathrm{.}25,40,80,30],[$Traffic Density,$0\mathrm{.}20,50,80,60],[$Neighbourhood Income,$0\mathrm{.}15,50,70,40],[$Zoning laws,$0\mathrm{.}10,80,20,90]]$

a$)$ At which site should Subway open the new restaurant? $(2$ marks$)$

b$)$ If the weights for Space and Traffic density are reversed, how would this affect the decision? $(2$ marks$)$