If a Firm's Promotional Budget Were Extremely Limited, for Which

If a firm's promotional budget were extremely limited, for which of the following reasons would it be more likely to rely on personal selling as its main promotional tool?

A) People are more likely to believe a human being than a print ad.
B) TV and radio ads are not feasible for smaller companies.
C) It can achieve more sales through business customers than through individual consumers.
D) It is easier to measure a salesperson's effects on sales than advertising's effects on sales.
E) The firm is charging a higher price to cover the expensive salaries of its salespeople.