Answer:
Running RECURSIVE-MATRIX-CHAIN is asymptotically more efficient than enumerating all the ways of parenthesizing the product and computing the number of multiplications of each.
the running time complexity of enumerating all the ways of parenthesizing the product is n*P(n) while in case of RECURSIVE-MATRIX-CHAIN, all the internal nodes are run on all the internal nodes of the tree and it will also create overhead.
Explanation: