Adjacent angles are those which are neighboring each other and share a vertex and a side.
Angles 2 and 4 are the only ones who share a vertex and a side (both of them are important), so that is the correct answer.
Hope this helps :)

Ashston2011

Adjacent angles would mean that the angles are next to each other, which means they have the same vertex, and share ONE side.
Angles 2 and 4 are adjacent.