My value for an air-conditioner in my office is $100. My office-mate's value of the air conditioner is $80. It is EFFICIENT for us to BUY the air-conditioner for our office. This means that the COST of the air-conditioner is ________. Pick the most accurate answer to fill in the blank. Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a Less than $80 b Less than $180 c less than 100 d less than 90