Answer:
C. Stealth marketing
Step-by-step explanation:
Stealth marketing refers to any forms of action that company take to promote its product without direct awareness from the customers. Even though stealth marketing tend to be really effective Typically this type of marketing is considered as an ethical and tend to offend their customers base.
Beside hiring strangers to talk positively about their product , other example of stealth marketing that often conducted by companies is by painting public properties with similar color and design to their brand logos.