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Consider the following statements with respect to control charts for attributes:

1. The lower control limit is non-negative

2. Normal distribution is the order for this data

3. The lower control limit is not significant

4. These charts give the average quality characteristics

Which of the statements given above are correct:

A) 1, 2 and 3                     

B) 2, 3 and 4

C) 1, 3 and 4                     

D) 1, 2 and 4