Consider a flow network G = (V, E, c, l, d) given to the problem of circulation with demands and lower bounds. Here, V is the set of nodes, E is the set of edges, c(e) and l(e) are, respectively, the upper bound and the lower bound of flow on an edge e E, and d(v) is the demand at a node d V. (a) briefly summarize the key idea for solving the circulation with demands and lower bounds problem by reducing (i.e., reformulating) it to the circulation with demands problem, and (b) give a sketch of the reduction algorithm that constructs a flow network G = (V, E, c, d) from G = (V, E, c, l, d) and give the reduction algorithms runtime complexity with an explanation assuming an adjacency list representation of the graph (V, E). Note that G has no lower bounds on its edges.