This is very brilliant question!
We have here, Edges E=6 and Vertices N=10.
A) Maximum Components:
For, Maximum components we should have maximum vertices are disconnected as possible. so for doing that we should have graph, which takes minimum vertices and maximum edges i.e. it is a Complete graph.
So, N(N-1)/2 =E = 6 {No. edges in complete graph}
::N=4
so, our 4 vertices are utilized to cover 6 edges or we can say we need atleast 4 vertices to cover 6 edges!
So, total components = 1 [complete graph] + 6 [all vertices 'single'] =7
B)Minimum Components
Logic is same but in reverse manner,thus 'we should find graph which take maximum vertices to cover all the edges' i.e. MST
N-1 =E =6 {no.of edges in MST}
::N=7
So,our 7 vertices are utilized to cover 6 edges or we can say we would have at most 7 vertices to cover 6 edges
So, total components = 1 [MST]+ 3 [all vertices 'single'] = 4
Ans is (C) M=7,m=4