#### Answer

We can make a spanning tree with the edges AB, AC, and CD.
We can make a spanning tree with the edges AB, AD, and CD.
We can make a spanning tree with the edges BC, AC, and AD.
We can make a spanning tree with the edges BC, CD, and AD.

#### Work Step by Step

The original graph has 4 vertices and 5 edges. If a tree has 4 vertices, then it must have exactly 3 edges. To make a spanning tree from the original graph, we need to choose 3 edges from the original graph.
We can make a spanning tree with the edges AB, AC, and CD.
We can make a spanning tree with the edges AB, AD, and CD.
We can make a spanning tree with the edges BC, AC, and AD.
We can make a spanning tree with the edges BC, CD, and AD.