Step 1: Understand the nature of marketing expenditure.
Marketing expenditure includes all costs associated with promoting products and services, such as advertising, sales efforts, and promotional activities.
Step 2: Evaluate the options.
- The burden of marketing expenditure ultimately falls on the customers, as businesses pass on the costs through higher prices for goods and services.
- While businesses and industries may incur these costs, customers bear the indirect burden.
Step 3: Conclude.
Thus, the correct answer is that the burden of marketing expenditure is primarily on the customers.
Final Answer:
\[
\boxed{\text{Customers}}
\]