If the good represented by the table is a public good, what is the market quantity demanded at $$14?\backslash$begin$\{$tabular$\}\{|$r$|$r$|$r$|$r$|$r$|\}$

$\backslash$hline & $\backslash$multicolumn$\{1\}\{|$c$|\}\{$ Dennis QD $\}$ & $\backslash$multicolumn$\{1\}\{|$c$|\}\{$ Charlie QD $\}$ & Mac QD $\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $1\backslash )$ & $5$ & $3$ & $7\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $2\backslash )$ & $4$ & $1$ & $6\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $3\backslash )$ & $3$ & $0$ & $5\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $4\backslash )$ & $2$ & $0$ & $4\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $5\backslash )$ & $1$ & $0$ & $3\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $6\backslash )$ & $0$ & $0$ & $2\backslash \backslash$

$\backslash$hline$\backslash (\backslash$$ $7\backslash )$ & $0$ & $0$ & $1\backslash \backslash$

$\backslash$hline

$\backslash$end$\{$tabular$\}$