A survey would be reliable if it had the same results, because then it would have been proven time and time again that it is credible. It is valid when it measures to what it intends to measure, because if it didn't, how would it be valid? In order for it to be valid, it has to make sense and measure what it intends to measure. The answer is D: reliable; valid.
The correct answer is concrete operational stage. This stage
is considered to be the third stage among the piaget’s theory of cognitive
development by which this period spans the time in terms of the middle
childhood and is being characterized through the development of the logical
thought.
