I tried this against a SQL Server 2008 R2 database and both 1 and 5 brought back the bracketed records. Luckily I choose answer 1.
Query 5 will bring back records that have characters before the bracket too. The question was for rows that begin with a bracket. Although in the example posted it brings back the same rows, if you run the queries against the table below the outcome will be different.
CREATE TABLE #MyData
('This is a string'),
('"A Quoted String"'),
('''Single quoted string'''),
('''more single quotes'''),
('AA[My bracketed string]'),
('[Can I find this string]')
On two occasions I have been asked, "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" ... I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.
—Charles Babbage, Passages from the Life of a Philosopher
How to post a question to get the most help http://www.sqlservercentral.com/articles/Best+Practices/61537