Ned Is Testing a Web Application

Ned is testing a web application. He visits a page that seems to have some features that can be customized by the user, but not all of them. He uses a cookie viewer to take a look at how his settings are stored and notices the following name value pairs:
Colorscheme=ocean
Layout=newspaper
Admin=false
He changes the admin variable to true, and reloads the page. This time he can change more items on the page. What is the name of this attack?

A) Parameter manipulation
B) Cookie triangulation
C) Cookie hijacking
D) Cookie stealing