Which command-line tool should you use?

You are developing an ASP.NET MVC application that will be deployed on a web farm.
Passwords must be stored in the web.config file and must not be readable or in a format that
is easily decodable You need to encrypt the passwords that are stored in the web.config file.
Which command-line tool should you use?

A.
Aspnet_regiis.exe

B.
Ngen.exe

C.
Aspnet_merge.exe

D.
EdmGen.exe