The correct answer is Tree as explained above.
Now some people may get confused regarding the correctness of this option as a tree may not necessarily connect all the vertices, which is true indeed. However, here we are not asked about the definition of tree. We are just given a scenario where we have a subset of edges that connects all the vertices and has minimum total weight. This is clearly a Minimum Spanning Tree and not any tree in general. However, an MST is still a tree (with some special properties) and so among the given options, Tree is correct.
Sometimes questions like this are given, where none of the options are 100% correct, so we have to choose the option which is closest to being correct.