The marketing communications strategy of the marketing mix deals exclusively with personal selling, advertising, sales promotion, and public relations (option C).

Personal Selling:
- Personal selling involves direct interaction between the salesperson and the potential customer. It is a form of communication where the salesperson presents the product or service to the customer, answers their questions, and persuades them to make a purchase. Personal selling is often used for high-value or complex products where a more personalized approach is required.

Advertising:
- Advertising is a paid form of communication that uses various media channels such as television, radio, print, outdoor advertising, and online platforms to reach a wide audience. It aims to create awareness, generate interest, and persuade customers to purchase a product or service. Advertising messages are usually designed to be persuasive and memorable.

Sales Promotion:
- Sales promotion consists of short-term incentives aimed at encouraging customers to make a purchase or take a specific action. It includes activities such as discounts, coupons, contests, giveaways, loyalty programs, and point-of-sale displays. Sales promotion helps to stimulate immediate sales and create excitement around a product or service.

Public Relations:
- Public relations (PR) involves managing the relationship between an organization and its various publics, including customers, employees, shareholders, media, and the general public. PR activities aim to build a positive image and reputation for the organization through activities such as media relations, press releases, events, sponsorships, and community outreach. PR helps to create a favorable perception of the organization and its products or services.

Importance of Marketing Communications Strategy:
- A well-developed marketing communications strategy is crucial for the success of any marketing campaign. It helps to ensure that the right message is delivered to the target audience through the most effective channels. By integrating personal selling, advertising, sales promotion, and public relations, a company can create a cohesive and consistent communication plan that maximizes its marketing efforts.

- Personal selling allows for direct interaction and customization based on individual customer needs.
- Advertising reaches a larger audience and creates brand awareness.
- Sales promotion provides incentives for immediate sales and encourages customer loyalty.
- Public relations builds credibility and enhances the organization's reputation.

In conclusion, the marketing communications strategy of the marketing mix involves personal selling, advertising, sales promotion, and public relations. These elements work together to create a comprehensive and effective communication plan that reaches the target audience, promotes the product or service, and builds a positive brand image.