Answer:The pool must have been the same depth at the start of the interval as it was at the end of the interval.
Step-by-step explanation:
The average rate of change is calculated as:
[final value - initial value] / time interval.
Then, the average rate of change does not take into account intermediates values, and you cannot draw any conclusion about such intermediate values.
In the given case you have:
average rate of change in depth = [final depth - initial depth] / 2 weeks.
0 = [final depth - initial depth] / 2 weeks.
⇒ 0 = final depth - initial depth
⇒ final depth = initial depth.
That is why the conclusion is the second statement of the answer choices: the pool must have been the same depth at the start of the interval as it was at the end of the interval.
In between the pool might have been deeper, more shallow, empty or change in any form, since the average rate of change does not tell the full history but only the net change.
