Which Formula Calculates the Variable Rate of a Mixed Cost $\frac{\text {high point output - low point output }}{\text {high point cost - low point cost }}$

Multiple Choice

Which formula calculates the variable rate of a mixed cost when using the high-low method?

A)
$\frac{\text {high point output - low point output }}{\text {high point cost - low point cost }}$
B)
$\frac{\text { high point cost - low point cost }}{\text { high point output - low point output }}$
C) total cost at high point - (variable rate × output at low point)
D) total cost at high point - (variable rate × output at high point)