Let {A} and {B} be two frequent itemsets of size one, and let {C} and {D} be two non-frequent itemset of size one. If possible, decide for the following itemsets, if they (i) must be frequent, or (ii) must not be frequent, or (iii) neither decision can be made. Explain your rationale in one sentence. 1.{A,B} 2.{C,D} 3.{B,C} A good choice of parameter k in the k-means algorithm is paramount to obtain a high-quality clustering. Explain (in 1-2 sentences each) what happens if k is chosen too large or too small.