Let $G$ be a weighted graph with edge weights greater than one and $G'$ be the graph constructed by squaring the weights of edges in $G$. Let $T$ and $T'$ be the minimum spanning trees of $G$ and $G'$, respectively, with total weights $t$ and $t'$. Which of the following statements is TRUE?

d will be the answer. t' may or may not b equal to t . if distict weight it will be equal and if same weight then diffrent structure may be obtained . plus the weight of t <= t'

Here D is correct. As everyone said B option is true but in one case it fails if there is a graph with 2 Nodes and edge weight is 1 then it t1==t^2, thus t1<t^2 will fail. And definitely MST doesn't change When edge weights are squared.