1. **State the problem:** Mabel needs to buy blueberries for $b$ batches of scones. Each batch requires 2 cartons, and each carton costs 4. 2. **Identify the formula:** Total cost = (number of batches) $ \times $ (cartons per batch) $ \times $ (cost per carton). 3. **Apply the values:** Total cost = $b \times 2 \times 4$. 4. **Simplify the expression:** $$b \times 2 \times 4 = 8b$$ 5. **Check the given options:** - $4(2b) = 8b$ (correct) - $2 + 4b$ (incorrect, addition not multiplication) - $4(b^2)$ (incorrect, no squaring involved) - $8b$ (correct) **Final answer:** The expressions that represent the total cost are $4(2b)$ and $8b$.