Antioch Extraction, which mines ore in Montana, uses a calendar year for both financial$-$reporting and tax purposes. The following selected costs were incurred in December, the low point of activity, when $1,500$ tons of ore were extracted:

Straight$-$line depreciation $ $25,000$

Charitable contributions$*$Footnote asterisk $11,000$

Mining labor$/$fringe benefits $345,000$

Royalties $135,000$

Trucking and hauling $275,000$

$*$Footnote asteriskIncurred only in December.

Peak activity of $2,600$ tons occurred in June, resulting in mining labor$/$fringe benefit costs of $$598,000,$ royalties of $$201,000,$ and trucking and hauling outlays of $$325,000.$ The trucking and hauling outlays exhibit the following behavior:

Less than $1,500$ tons $ $250,000$

From $1,500$ to $1,899$ tons $275,000$

From $1,900$ to $2,299$ tons $300,000$

From $2,300$ to $2,699$ tons $325,000$

Antioch uses the high$-$low method to analyze costs.

Required:

$1.$ Classify the five costs listed in terms of their behavior: variable, step$-$variable, committed fixed, discretionary fixed, step$-$fixed, or semivariable.

$2.$ Calculate the total cost for next February when $1,650$ tons are expected to be extracted.

$3-$a$.$ Is hauling $1,500$ tons with respect to Antioch$$s trucking$/$hauling cost behavior cost$-$effective?

$3-$b$.$ If the company goal is $1,500$ tons, what is the maximum number of tons at which cost$-$effectiveness can be achieved?

$4.$ Distinguish between committed and discretionary fixed costs. If Antioch were to experience severe economic difficulties, which of the two types of fixed costs should management try to cut?