Final answer:
The conditioned response in the advertisement scenario is attraction/desire, which is the result of associative learning where the car is linked with positive stimuli like attractive women.
Step-by-step explanation:
In the scenario you've described where market researchers have found that straight men are more likely to buy a car after viewing an advertisement that includes attractive women sitting on the cars, the conditioned response is a) attraction/desire. This is based on the principles of associative learning, where the presence of hot women creates a positive association with the car, leading men to perceive the car as more desirable. This form of advertising has been found to alter perceptions and increase the appeal of products.