Learning Curve BPP Qution number 142

Dear Tr.Moffat,

Let me copy from the other student question and you said that correct answer is Number C instead of D.

The following statements have been made about learning curves.
(1) learning curves are easier to apply in companies with high labour turnover than those with lower rate of staff turnover
(2) learning rates are not affected by time gaps between the production of additional units of a product.
Which of the following statements are true?

A. 1 only
B. 2 only
C. Neither 1 nor 2
D. Both 1 and 2

Answer from BPP – C
But i do not understand, why number 2 is wrong?
If time gap happen, learning rates are not affected?

Thanks.

May