# Quiz

+ What are the following statements about TiKV data persistence incorrect?
  + `A` . RocksDB has 2 instances, each for persisting raft log and key value data
  + `B` . WAL in.rocksDB is used to ensure that writes are not lost
  + `C` . For delete operations, you only need to mark the original key value data as deleted
  + `D` . RocksDB, except for Level 0 level data, all other Levels are single-sorted and persistent

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C