Which code segment should you execute?

Explanation/Reference:
Note:
Locking the table during the process and not recomputing statistics would be the fastest.
* Online = OFF
Table locks are applied for the duration of the index operation. An offline index operation that creates, rebuilds, or drops a clustered, spatial, or XML index, or rebuilds or drops a nonclustered index, acquires a Schema modification (Sch-M) lock on the table. This prevents all user access to the underlying table for the duration of the operation. An offline index operation that creates a nonclustered index acquires a Shared (S) lock on the table. This prevents updates to the underlying table but allows read operations, such as SELECT statements.
* STATISTICS_NORECOMPUTE = ON
Out-of-date statistics are not automatically recomputed.
Reference: ALTER INDEX (Transact-SQL)