The correct answer is: Only III is implicit.
The statement is an advertisement for Riya cold cream. Advertisements are designed to persuade people to buy a product or service. In this case, the advertisement is trying to persuade people to buy Riya cold cream by claiming that it will make their complexion fairer.
Assumption I is that people like to use cream for fair complexion. This assumption is not implicit in the statement. The statement does not say anything about whether or not people like to use cream for fair complexion. It is possible that some people do like to use cream for fair complexion, while others do not.
Assumption II is that people are easily fooled. This assumption is also not implicit in the statement. The statement does not say anything about whether or not people are easily fooled. It is possible that some people are easily fooled, while others are not.
Assumption III is that people respond to advertisements. This assumption is implicit in the statement. The statement is an advertisement, and it is designed to persuade people to buy Riya cold cream. This means that the advertiser believes that people will respond to the advertisement.
Therefore, the only assumption that is implicit in the statement is assumption III.