Using the data set below, what would be the forecast for period $5$ using a four period weighted moving average? The weights for each period are $0\mathrm{.}05$;$0\mathrm{.}15,0\mathrm{.}30,$ and $0\mathrm{.}50$ from the oldest period to the most recent period, respectively. $($Choose the closest answer.$)$

$\backslash$table$[[$Period$,$Actual Demand$],[1,11,900],[2,12,500],[3,14,325],[4,15,750],[5,10,500],[6,15,500]]$

a$.13,269$

b$.13,710$

c$.13,619$

d$.15,238$