You are developing an ASP.NET MVC application that reads and writes data from a SQL Server database.
You need to maintain data integrity in all situations that use transactions.

A.
ReadUncommitted

B.
Repeatable

C.
Serializable

D.
ReadCommitted

Explanation:
The highest isolation level, serializable, guarantees that a transaction will retrieve exactly the same data every
time it repeats a read operation.
https://technet.microsoft.com/en-us/library/ms189122(v=sql.105)