4. (36 points) A sequence database SDB1 (Table 3) has 5 transactions, and we will consider frequent sequential pattern mining with (absolute) minimum support of 2. (a) (3 points) What are the length-1 frequent sequential patterns in SDB, and what are their supports? (b) (5 points) What is the projected database for prefix (bb)? Is (bb) a length-2 frequent pattern in SDB1? What is the support of (bb)? (c) (5 points) What is the projected database for prefix ((bd))? Is ((bd)) a length-2 frequent pattern in SDBi? What is the support of ((bd))? 3 Sequence_ID Sequence S1 (bd) cb(ac)) S2 ((bf) (ce) b(fg)> S3 ((ah) (bf)abf) SA ( (be) (ce)d) S5 (a(bd) bcb(ade)) Table 3: A sequence database SDB1. (d) (4 points) What is the projected database for prefix (b)? (e) (8 points) Using the projected database for prefix (b), find all frequent subsequences starting with b. Please list your answer in lexicographically ascending order. (f) (4 points) What is the projected database for prefix (c)? (g) (7 points) Using the projected database for prefix (c), find all frequent subsequences starting with c. Please list your answer in lexicographically ascending order