Chem test question and how to troll it - 2

Ok, came up with another chem test trolling question.
Basically it's another 'discrimination question' from a chem test. So here is the question itself (around there):
A student weighed 1.0 g of manganese (IV) oxide and added to 20 cm3 of 1.0 mol/dm3 hydrogen peroxide. After all effervescence has stopped, the student filtered the mixture and dried the residue in an oven of 60oC for 1 hour. After that, he weighed the mass of manganese (IV) oxide again.
Question: Identify one mistake made by the student.
Answer: Anyways, the correct (two) answers to the question is somewhat urgh stupid and over common sense that normally people are unable to think of it. The first answer is that he forgot to wash the residue with deionised water because there may be contaminent present on the residue that may affect the mass of the manganese (IV) oxide. I would call it stupid because the products of breakdown of hydrogen peroxide are water and oxygen. Since the breakdown is already complete (shown from the stopping of effervescence), there is no point washing with deionised water because there is water itself. But it is a well SPA technique, so the answer is considered as correct.
The second answer is that the student should not heat the manganese oxide at 60oC because the temperature is too low for all the water to evaporate, thus it should be heated at a higher temperature. Majority of the people cannot think of this answer because the 'for 1 hour' misled them. (I also thought 1 hour is enough for water to evaporate, even at 60oC, but still..)
Anyways, after the formal answering, methods to troll the question.
Method 1:
Write 'The student did not make any mistake'. Of course you will be marked wrong, but you can always argue that the teacher did not make the question obvious enough so you cannot find any flaws. Boring method because people already tried that.
Method 2:
Write 'The student did not carry out the experiment in the presence of a teacher. SPA SKILL OK.' Since it is assumed that the student is allowed to conduct the experiment, so that's a 0 as well. But well you can always say the teacher never specify...
Method 3:
Copy the whole question again. Technically the answer IS within the answer you gave..so you might get a half mark for that. But alternatively, the teacher will surely see that you are trying your luck, so that's a cross.
Method 4:
Write the PERFECT BIO ANSWER XDXDXD. Something like 'the student did not triplicate his result / the student did not triplicate the whole experiment to test the reproducibility of the experiment' IT'S THE PERFECT BIO ANSWER. ZERO MARK FOR CHEM TESTS. quoted from a very reliable source 'It can be accepted for SPA, but since i gave you the passage with the answer inside, of course you need to look inside the passage for the answer. dont give me such vague answer.' - very reliable source, do not question it.