The correct answer to this open question is the following.
Although the question does not include options, we can say the following.
On his second missionary journey, Paul receives a vision at Troas that encourages him to travel to Macedonia.
In his second missionary journey, Apostle Paul took Silas with him and the go to the region that today is Turkey. With the help of another disciple named Timothy, Paul wants to spread the word of God in this region of Asia, but it is said that he refrained to do so because the Holy Spirit prevented him. Then, in the city of Troas, Paul has this vision: he sees a man from Macedonia who is asking for help. Paul considered that this is the call of God, to go to Macedonia and evangelize.