I have an explain plan query and I need to call with parameters in my .Net application. When I try it as following it gives me ORA-1780 Error. I have many parameterized queries in my application but this script is not working. How could I fix it?

private static readonly string sql =@"EXPLAIN PLAN SET STATEMENT_ID = :statementId FOR :sqlScript";

  using (OracleCommand cmd1 = new OracleCommand(PrepareCostOracleSqlPattern, con))
  {
                        cmd1.Parameters.Add(new OracleParameter("statementId", statementId));
                        cmd1.Parameters.Add(new OracleParameter("sqlScript", sqlScript));
                        cmd1.CommandTimeout = 6000;
                        object result = cmd1.ExecuteNonQuery();
  }

ORA-01780: string literal required