Answer: D. Replicate the experiment to see whose results are more reliable.
Step-by-step explanation:
The experiments are similar, then we should expect to see similar results.
Now, we know that they get different results, let's analyze the options:
A) With the given information we can not conclude which is the incorrect experiment, then this is discarded.
B) We can not really determine that both students are in correct only knowing the experiment and the results, so this is also discarded.
C) You can not assume things.
D) This is the correct option, an experiment must be repeatable. This means that, with the same conditions, the result must be always the same.
Then we can replicate both experiments and see if the results are the same as before to determine if the results are reliable.