Final answer:
The use of a third-party testimonial letter strengthens the counterclaim method of responding to a prospect's objection.
Step-by-step explanation:
The use of a third-party testimonial letter strengthens the counterclaim method of responding to a prospect's objection. When a prospect raises an objection, providing a third-party testimonial can help support the counterclaim by offering evidence or proof that contradicts the objection. This can be particularly effective if the testimonial comes from a reputable source or a satisfied customer.