I'm pretty sure those are all different dates, actually. The number 21 is the year, not the day, and the day is not shown.
The number in parentheses is the number of days from today to expiry. So, assuming you took that screenshot today (May 26, 2021), the expiry dates for the first few options listed are:
- Wednesday, May 26 (today)
- Friday, May 28 (2 days from now)
- Wednesday, June 2 (7 days from now)
- Friday, June 4 (9 days from now)
- Friday, June 11 (16 days from now)