You have a database that contains a table named Customer. The customer table contains a column named LastName that has a column definition of varchar(50).
An application named App1 reads from the table frequently.
You need to change the column definition to nvarchar(100). The solution must minimize the amount of time it takes for App1 to read the data.
Which statement should you execute?
A. 
B. 
C. 
D.
A. Option A
B. Option B
C. Option C
D. Option D
Explanation:
To change the data type of a column in a SQL Server (or Microsoft access) table , usethe following syntax:
ALTER TABLE table_name
ALTER COLUMN column_name datatype
References: https://www.w3schools.com/SQl/sql_alter.asp