Answer: (B.) If the maximum that a consumer is willing and able to pay is greater than the minimum price the producer is willing and able to accept for a good.
Step-by-step explanation:
A producer will only sell goods and services if the consumer is willing to pay as much as the asking price. i.e. The price that the producer is asking. For this to happen the consumer's willingness to pay must be greater than the minimum price.
Therefore , the trade will take place if the maximum that a consumer is willing and able to pay is greater than the minimum price the producer is willing and able to accept for a good.