Certainly prog rock. For me, I define progressive rock in very fundamental terms:

1. Experimental in nature. Either weird tempos or weird instruments make an appearance.

2. Unconventional narratives and lyrics.

3. Orchestral tendencies. Wind or string instruments tend to have a major role.

4. Abrupt changes in the middle of a song. It's like having multiple songs within one.

5. Long ass tunes. Not necessary in the strictest of terms but having 8 minutes or longer songs in an album with very long solos is a definite indication.