within the relevant range, variable costs can be expected to\nremain constant in total as the activity level…

within the relevant range, variable costs can be expected to\nremain constant in total as the activity level changes.\nvary in total in direct proportion to changes in the activity level.\nincrease on a per unit basis as the activity level increases.\nincrease on a per unit basis as the activity level decreases.

within the relevant range, variable costs can be expected to\nremain constant in total as the activity level changes.\nvary in total in direct proportion to changes in the activity level.\nincrease on a per unit basis as the activity level increases.\nincrease on a per unit basis as the activity level decreases.

Answer

Brief Explanations:

Variable costs are costs that change in relation to the level of production or activity. For example, if a company makes more widgets, the cost of raw materials (a variable cost) will increase. The key property of variable costs within the relevant range is that the total variable cost varies directly with the activity level. If the activity level doubles, the total variable cost also doubles. On a per - unit basis, variable cost remains constant. For instance, if it costs $5 of raw materials to make one widget, it still costs $5 per widget when making 100 widgets (total variable cost is $5\times100 = 500$).

Answer:

vary in total in direct proportion to changes in the activity level.