Mr$.$ Mokhtar is considering opening a new foundry in Kajang, BB Bangi and Semenyih to produce high$-$quality product X $.$ He has assembled the following fixed cost and variable cost data:

$\backslash$table$[[$Location$,$Fixed cost per,Per unit costs $($RM$)],[,$year $($RM$),$Material,Labor,Overhead$],[$Kajang$,200,000,\mathrm{.}20,\mathrm{.}40,\mathrm{.}40],[$BB Bangi,$180,000,\mathrm{.}25,\mathrm{.}75,\mathrm{.}75],[$Semenvih$,170,000,1\mathrm{.}00,1\mathrm{.}00,1\mathrm{.}00]]$

a$)$ Graph the total costs line

b$)$ Over what range of annual volume is each facility going to have a competitive advantage?

c$)$ What is the volume at the intersection of the BB Bangi and Semenvih cost lines?