Final answer:
Buyers are willing and able to pay up to $80 for 100 units of the product.
Step-by-step explanation:
The highest price that buyers will be willing and able to pay for 100 units of this product can be determined by looking at the demand curve. In the diagram, the demand curve intersects the quantity axis (Qd) at a price of $80 for 100 units. This means that buyers are willing and able to pay up to $80 for 100 units of the product. Therefore, option B, $60, is the correct answer.