Question: What opera company has its permanent home as he Staatsoper Unter den Linden and had Franz Betz as an opera singer in the 1800's?
Sentence (from "Berlin State Opera"): Originally the "Hofoper" (court opera) from 1742, it was named "Königliches Opernhaus" (Royal Opera House) in 1844, and "Staatsoper Unter den Linden" in 1918.
Relevant evidence: No