Final answer:
The correct term is 'unsuspecting,' advising caution towards deceptive advertising and emphasizing critical thinking and skepticism.
Step-by-step explanation:
The term that best matches the advice 'Don't be naive enough to believe commercials and online ads that promise instant riches, effortless weight loss, and valuable free prizes' is unsuspecting. People who are unsuspicious or trusting can be easily misled by false promises.
This aligns with the broader advice provided which suggests that individuals should employ critical thinking when encountering claims especially in advertisements, as many appeals target the gullibility of consumers.
Being wary of exaggerated claims in media and advertising is advised, and a strong level of scrutiny is necessary for analyzing such offers since they may lead to decisions that could have negative consequences. The Federal Trade Commission checks factual claims to some extent, but consumers are reminded of the adage 'Caveat emptor'—let the buyer beware.
Therefore, individuals should be cautious, think critically, and not quickly divulge personal information or money based on appealing but potentially deceitful offers.