Date applicant first became qualified to practice this occupation

Hi

I am applying for Canada PR. I have a Masters from US and Bachelors from India. Per this thread, Express Entry application avoiding ECA for Bachelor's when MS highest, I just did WES for Masters and entered Masters details in Education section of the form.

Have 3 yrs of experience in India and 2+ in US, so, for work history and “Date applicant first became qualified to practice this occupation?” should it be Masters graduation date or Bachelors?

Thanks in advance!

Mohit