1. **Problem:** Find the coefficient of $xy$ in the expression $3xy - 7xy - 2x^3$. 2. **Formula and rules:** The coefficient of a term is the numerical factor multiplying the variables. Here, we look for terms containing $xy$. 3. **Intermediate work:** $$3xy - 7xy - 2x^3 = (3 - 7)xy - 2x^3 = -4xy - 2x^3$$ 4. The coefficient of $xy$ is therefore $-4$. 5. **Answer:** None of the options (a) 3x, (b) -2, (c) 7yz, or (d) ? matches $-4$. The coefficient is $-4$. Since the question asks for the coefficient of $xy$ in the expression, the correct coefficient is $-4$. **Final answer:** $-4$