You need to design a package to change a variable value during package execution by using the least amount of development effort

You are developing a SQL Server Integration Services (SSIS) package.
You need to design a package to change a variable value during package execution by
using the least amount of development effort.
What should you use?

A.
Expression task

B.
Script task

C.
Execute SQL task

D.
Execute Process task

E.
Term Extraction transformation

Explanation:
Reference:
http://msdn.microsoft.com/en-us/library/hh213137.aspx