What is required of powerboat A when approaching sailboat B heading in darkness or reduced visibility?

When powerboat A approaches sailboat B in darkness or reduced visibility, it is required to exercise caution and take steps to avoid a collision. Powerboat A, being the give-way vessel, should reduce speed and maintain a proper lookout to assess the situation. Additionally, it must comply with navigation rules, which may involve altering its course to ensure safe passage around the sailboat, while also being aware of any sound signals that may indicate the sailboat's intentions.