Answer: induce too much fear
Step-by-step explanation:
Ineffectiveness of advertisement is caused when audience is not able to understand actual purpose and message behind the ad. Showing too much fear can threaten audience in a way that they misinterprets message of advertisement and thus, not able to follow value of ad.
According to the question,anti-smoking ad for quitting smoking habit of people is used as message behind the ad.Displaying too much scaring photographs related with smoking habit will induce fear in people and they will not be able to understand real intention of ad.