Final answer:
The firm's competitive environment is usually beyond the control of the marketing manager, as it is influenced by external market structure factors, unlike the firm's distribution methods, salesforce, and advertising efforts.(Option b)
Step-by-step explanation:
The option that is usually beyond the control of the marketing manager is The firm's competitive environment. While marketing managers can influence the firm's method of distribution, salesforce, and advertising campaigns, the competitive environment is largely determined by external factors such as the number of competitors, the market power of each firm, and the overall market structure.
Market structure is crucial as it involves the production and cost conditions facing each firm and how competitive the industry is. This aspect is outside the remit of the marketing manager, who typically focuses on strategies within the firm that can include successful advertising campaigns aimed at making a firm's products appear differentiated and desirable to consumers, thus affecting the firm's perceived demand curve and potentially increasing quantity sold and price.