Final answer:
The unpopularity of direct mail in Chile is mainly because customers must pay for each item delivered by the letter carrier. Global communication trends indicate a preference for digital messages over traditional postal services, influencing the demand for direct mail.
Step-by-step explanation:
The unpopularity of direct mail as a medium in Chile is not due to low literacy levels, environmental concerns, or extensive government regulations. Instead, the correct answer is option b), which states that customers must pay for every item delivered by the letter carrier. This model discourages the use of direct mail for both senders and recipients, as it imposes an additional cost on the latter.
Additionally, it is noteworthy that other forms of communication, such as digital messages and social media, are increasingly more popular. This shift in communication preferences aligns with global trends where the viability of traditional postal services is challenged by rising costs and a move towards digital alternatives, leading to a decline in demand for post-delivered mail.