Select the statements below which are TRUE: Let X = , Y = and Z = . Then Z is a common subsequence of X_7 and Y_4. Let X = , Y = and Z is a common subsequence of X and Y. Let = and Y = . Then Y is a subsequence of X. Let X = . Then X_5 = . Let X = and Y = . Let Z be a longest common subsequence (LCS) of X_m-1 and Y_n - 1. Then appending A to the end of Z produces an LCS of X and Y