Whizlabs replied me and they pointed me to the "minusYear" method, as you see in the screenshot, the s is missing :/
So, it´s not minusYear. It´s minusYears, in the plural, so last lastYear1 and lastYear2 are the correct ones.
Now, a question for you guys which, of course, are more experient than me, does this kind of question really appear in the exam?
Thanks!