题目A和D选项区别是什么？

Standard costing card - Product 123

$

Direct material (standard quantity × standard price)

material X - 3kg at $4 per kg

12

material Y - 9litres at $2 per litre

18

Direct labour (standard time × standard rate)

  grade A - 6hrs at $1.5 per hr

9

  grade B - 8hrs at $2 per hr

16

Standard direct cost

55

Variable production overhead (14hrs × $0.5 per hr)

7

Standard variable cost of production

62

Fixed production overhead (14hrs × $4.5 per hr)

63

Standard full production cost

125

Administration and marketing overhead

15

Standard cost of sales

140

Standard profit

20

Standard selling price

160

Ideal

（理想标准成本）

▪ Based on perfect operating conditions: no wastage, no spoilage, no inefficiencies, no idle time, no breakdowns.

▪ Unfavourable motivational impact because reported variances will always be adverse.

Attainable

（正常标准成本）

▪ Some allowance is made for wastage and inefficiencies.

▪ Provide a useful psychological incentive but challenging target of efficiency.

Current

（现行标准成本）

▪ Based on current working conditions (current wastage, current inefficiencies).

▪ They do not attempt to improve on current levels of efficiency.

Basic

（基本标准成本)

▪ Kept unaltered over a long time, and may be out of date.

▪ Used to show changes.

▪ Least useful and least common type of standard.