Answer:
He should have given the Japanese negotiators a menu of options including the lower price.
Step-by-step explanation:
As it was already on cards that whenever you negotiate you need to have some preparation beforehand and have a complete list of options you would opt if your best options fails to be executed.
Hence, Mike should have given the Japanese a list of options so that It would be easy for them to think about the offer as well as give Mike the advantage to make his deal a success through different options. And if still the options weren't good enough for the Japanese, then Mike would only be left with the option of lowering the price but he would still had a more chance of getting his deal done if he had prepared those options as well.
Thanks.
Goodluck buddy.