To insert "Olsen" as the "LastName" in the "Persons" table using SQL, you can use the following syntax:

B. INSERT INTO Persons (LastName) VALUES ('Olsen')

Explanation: Option A: INSERT ('Olsen') INTO Persons (LastName) - This is an incorrect syntax. The correct syntax for the INSERT statement requires the keyword "INTO" before the table name, followed by the column names in parentheses, and the keyword "VALUES" before the values to be inserted.

Option B: INSERT INTO Persons (LastName) VALUES ('Olsen') - This is the correct syntax. It specifies the table "Persons" and the column "LastName" where the value 'Olsen' will be inserted.

Option C: INSERT INTO Persons ('Olsen') INTO LastName - This is an incorrect syntax. The correct syntax for the INSERT statement requires the keyword "VALUES" before the values to be inserted.

Option D: INSERT FROM Persons ('Olsen') INTO LastName - This is an incorrect syntax. The correct syntax for the INSERT statement does not include the keyword "FROM" before the table name, and the column name should be specified before the keyword "VALUES".

Therefore, the correct answer is B. INSERT INTO Persons (LastName) VALUES ('Olsen').

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• Wrong explanation

To return the number of records in the "Persons" table using SQL, you can use the COUNT(*) function.

Let's go through each option to understand why it is correct or incorrect:

Option A) SELECT COUNT() FROM Persons - This option is incorrect because the COUNT() function requires an argument. The argument specifies the column or expression to count. Without the argument, the function will produce an error.

Option B) SELECT COLUMNS() FROM Persons - This option is incorrect because there is no COLUMNS() function in SQL. To select all columns from a table, you can use the * wildcard.

Option C) SELECT COLUMNS(*) FROM Persons - This option is incorrect because there is no COLUMNS() function in SQL. To select all columns from a table, you can use the * wildcard.

Option D) SELECT COUNT() FROM Persons - This option is correct because it uses the COUNT() function to count all records in the "Persons" table. The COUNT(*) function returns the number of rows in the specified table.

The correct answer is D. This option is correct because it uses the appropriate COUNT(*) function to return the number of records in the "Persons" table.

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• Wrong explanation