Consider the demand data listed below. What is the $4-$month moving average forecast for June?

$\backslash$table$[[$Month$,$Actual Demand$],[$Jan$.,10,000],[$Feb$.,12,000],[$Mar$.,21,000],[$Apr$.,9,000],[$May$,18,000]]$

a$)15,000$

b$)14,333$

c$)16,000$

d$)13,500$

e$)23,333$