(a) List all the 4-subsequences contained in the following data sequence:
< {1, 3} {2} {2, 3} {4} >,
assuming no timing constraints.
(b) List all the 3-element subsequences contained in the data sequence for part (a) assuming that no timing constraints are imposed.
(c) List all the 4-subsequences contained in the data sequence for part (a) (assuming the timing constraints are flexible).
(d) List all the 3-element subsequences contained in the data sequence for part (a) (assuming the timing constraints are flexible).