Question 4 ( 20 points) Given the below four faces, darkness or number of dots represents density. Lines are used only to distinguish regions and do not represent points. For each figure, could you use partition, hierarchical, density, and other algorithms we learned in class to find the patterns represented by the nose, eyes, and mouth? Please list at least 3 different types of algorithms and explain the pros and cons of each. (a) (b) (c) (d)