Please help me with this question, thanks!

(a) Recall that the complete bipartite graph Km.\" is the bipartite graph with bipartition {11,3} such that |A| = m,|B| = n and every vertex in A is adjacent to every vertex in B, where m and n are positive integers. Prove that 5(Km'n} = A(Km.n) = n1in{m.,n}. (b) A connected graph is called unicyclic if it contains exactly one cycle. Prove that the edge-connectivity of any unicyclic graph is at most 2