The __________ is used for an event that continues to occur at the present moment in time.
Present progressive, or present continuous is the correct answer. That is the tense that we use if we want to show a continued or ongoing activity in the present.(e.g. "I am reading a book." It means that I am currently in the process of reading a book). So, actions that are happening at the time of speaking, such as this one are expressed by Present continuous/progressive.