_______ is an impersonal form of communication by a marketer to promote a product.

Option 1 -> Personal Selling involves direct, face-to-face interaction between a salesperson and customer, making it a personal form of communication, not impersonal.

Option 2 -> Advertising is a paid, impersonal mass communication tool that reaches a large audience through media channels (TV, radio, print, digital) without direct personal interaction.

Option 3 -> Labelling is primarily used for providing product information, ingredients, and legal details rather than being a promotional communication tool.

Option 4 -> Packaging serves to protect, contain, and identify products; while it may support promotion, it's not primarily a communication tool for promotion.

Hence, Option 2: Advertising -> Advertising is a non-personal, mass communication method where marketers use paid media channels to reach and influence a large audience simultaneously without direct personal contact, making it the perfect example of impersonal promotional communication -> correct