suppose we are given a directed graph G$($V$,$E$)$ with non negative costs c$($e$)$ on edges. let T be a minimum spanning tree in G$.$ Let G$\text{'}$ be a graph obtained from G by adding an edge$=($u$,$w$)$ with c$($e$)=40$

a$)$ Give an instance where T is a MST in G$\text{'}$

b$)$Give an instance where T is not a MST in G$\text{'}$