How does Chapter 17 use an analogy to explain the choice between the pleasant and the good, and who is capable of making the right choice?

In Chapter 17, the text presents a powerful analogy to illustrate the choice between Shreya (the good) and Preya (the pleasant). It compares the two blended paths to a mixture of milk and water. Just as a swan, or Maral, is said to be able to drink only the pure milk from this mixture, a wise, courageous, and intelligent person can discern and cling only to Shreya. This chapter explains that those who are dull-witted and lack discrimination are incapable of making this distinction and are instead conquered by the allure of Preya, embracing it despite its detrimental effect on their true self-interest.