Final answer:
The main effect of the analogy in the sentences is that the reader knows that the boss is taking advantage of his employees.
Step-by-step explanation:
The main effect of the analogy in the sentences is that the reader knows that the boss is taking advantage of his employees.
The analogy used here is 'if it walks like a duck and it quacks like a duck, then it's probably a duck.' This analogy suggests that the behavior of the boss resembles the exploitative nature of a duck, indicating that the boss is taking advantage of the employees.
Therefore, option c) 'The reader knows that the boss is taking advantage of his employees' is the correct main effect of the analogy in the sentences.