Which of the following actions is considered trading in real estate?

The action of hosting an open house for another salesperson is considered trading in real estate because it involves engaging in activities aimed at facilitating the sale or lease of real property. This action is part of the real estate transaction process, as hosting an open house directly supports the marketing and selling of a property, which is a fundamental part of a real estate professional's responsibilities.

In contrast, providing general property advice to friends does not typically involve a professional transaction or compensation, thus falling outside the realm of trading. Posting a personal blog about home improvements is more focused on sharing personal insights rather than engaging in real estate activities for others. Similarly, posting a weekly blog on marketing or real estate topics can be seen as a contribution to the field, but it does not involve direct transactional work or interaction with clients or properties. Therefore, while these other actions contribute to the real estate community, they do not qualify as trading in real estate, making hosting an open house the only correct choice in this scenario.