Can You Help Me Answering Some SQL Objective Question ??

i am unable to solve/answer this question related to sql... anybody ..!!??
[i am reposting my queries.. as before i posted in the wrong forum section.. so pease bear with me... Thanx] 
 Q-1: How would you add a country field to your database to ensure that your Argentinean subsidiary does business only with other Argentinean companies?

a) CHECK constraint
b) PRIMARY KEY constraint
c) FOREIGN KEY constraint
d) DEFAULT constraint

Q-2: You want to set up replication between two databases, so the financial data and the sales data will be the same. You want the data to replicate at 1:00 a.m. every morning. You would like to completely remove all data from the financial database each night and overwrite data from the sales database. Which database replication model would you choose?

a) Transactional replication
b) DTC replication
c) Subscriber replication
d) Snap shot replication
e) Merge replication

Q-3: Your company has 3 offices each of which is responsible for sales in their respective territory. Which of the following actions should you take to ensure a successful merge replication among you three offices?

a) You must include all tables with primary keys that are referenced by the foreign keys in the replicated tables
b) Prior to merge replication, create a unique identifier column in each table that are to be included in the publication
c) Do nothing, DTS will take care of it.
d) Prior to merge, you must create an index in the tables that are to be included in the publication.

Q-4: The SQL server that Michael manages crashed. The disk drives were not damaged but there was data that had not been written to some databases. Which transactions will be rolled forward in each database when his SQL server starts the automatic recovery process?

a) All committed transactions that are in the transaction log between the last checkpoint and the failure
b) All committed transactions that are in the transaction log
c) All committed transactions that are in the transaction log between the last two checkpoints
d) All uncommitted transactions that are in the transaction log

Q-5: What can occur when multiple users try to access the same schema object

 

Thanx in Advance..