TNA LABU Rolldowns

I said these would be easy to roll:
Bought to Close 1 TNA Aug 20 2021 79.0 Put / Sold to Open 1 TNA Aug 27 2021 75.0 Put at $0.05 Credit
Bought to Close 1 LABU Aug 20 2021 50.0 Put / Sold to Open 1 LABU Sep 03 2021 45.0 Put at $0.15 Credit.
(Why are there no strike prices available in LABU below 50 except for the strike 45?? What about a 49 or 48?)