Mr Jones Has Demonstrated That His Experimental Reading Program Is

Mr. Jones has demonstrated that his experimental reading program is very effective with 4th and 5th grade children with a learning disability. Ms. Thornton is using his experimental reading program but does not use it exactly like the instructions specify. Although Ms. Thornton has varied the way in which she is implementing the reading program she also finds it to be very effective with her students with learning disabilities. This is a demonstration that the reading program has:

A) Population validity
B) Temporal validity
C) Ecological validity
D) Treatment variation validity