So I was denied a student visa to the US back in 2017 (that's my first application) and I got my visa the second time. However, I failed to disclose it in the form IMM5709e (study permit extension) because I assumed the question "Have you ever been denied a visa or permit for canada or any other country or territory?" applied to Canada only (my mistake, I didn't read the question properly) and I answered it no. So now I am being extra careful in my post-graduate work permit application and answered it as yes this time explaining the details. Do I need to include a letter of explanation on why I answered no in the previous application? Kindly let me know!