If you are HSA eligible, then your CDHP must include or be part of an HDHP. So you can check the HDHP box.
This previous TT answer may provide clarification: https://ttlc.intuit.com/questions/3500637-i-was-wondering-if-hdhp-and-cdhp-are-considered-the-same-p...
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
