# Quiz

+ What are the following statements about the execution process of DDL statements?
  + `A` . DDL statements can be executed in parallel in TiDB
  + `B` . There can be no more than one DDL statement waiting to be executed at the same time
  + `C` . At the same time, only one TiDB server can execute DDL statements
  + `D` . DDL statements waiting to be executed are persisted in TiDB Server's storage

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C