Monday and Tuesday
Tuesday. Normal business days are Monday through Friday. Therefore Monday would be business day #1, Tuesday would be business day #2.
However you are the same person who asked about a check which was deposited taking two business days to clear. That means Monday and Tuesday. The money would be available to you Wednesday.
Make up your mind and since you've asked about this 3 times, I'd say enough already – unless you have something else to add which you didn't tell us about which would change the answer.
Business days are weekdays. Just don't count the weekends.
Monday if starts on Friday, if exclude Friday, then is Tuesday