A number of graphs displaying cost behavior patterns are shown on the next page. The vertical axis on each graph represents total cost and the horizontal axis represents the level of activity (volume),

- Cost of raw materials. where the cost starts at $7.50 per unit and then decreases by 5 cents per unit for each of the first 100 units purchased, after which it remains constant at $2.50 per unit.

Which chart? Please explain the logic.

In other posts you picked 2) but the cost is decreasing, not increasing.

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