Ladder Company wants to develop a cost$-$estimating equation for its monthly cost of electricity. It has the following day

$\backslash$table$[[$Month$,$Cost of Electricity,Direct Labor Hours$],[$February$,$$$8,100,750],[$May$,9,000,850],[$August$,10,200,1,000],[$November$,8,700,800]]$

Using the high$-$low method, which of the following is the best equation?

a$.Y=$$$2,400$ $$8,40x$

b$.Y=$$$1,800$ $$8,40x$

c$.Y=$$$900$ $$12\mathrm{.}00x$

d$.y=$$$900$ $$8\mathrm{.}40x$