Why did Paul preach in the synagogues first?

As we read the Newer Testament, called by some "the Apostolic Witness," we find Paul, the apostle to the Gentiles routinely going to the synagogues of his day. But why did he go there considering the fact that he was the Apostle ( to the Gentiles?

I usually think of three answers to this question.

1. He went to the synagogues because he was a Jew and he could always be found in synagogue on the sabbath, where he worshiped with his people..
2. He went to the synagogues because he operated on a principle of "to the Jew first," so that even though he was the Apostle to the Gentiles, the Jews had priority in every locale where he preached his message.
3. He went to the synagogue because that was where he would find Gentiles open to the biblical worldview, and therefore, more likely receptive to his message.
4. A fourth explanation is that Paul went to the synagogues because he wanted to recruit the Jews to go to the Gentiles with the message that the Messiah had come.

He knew that the prophets had predicted that the final deliverance would begin with the Jews and then go to the nations. He believed that with the resurrection of Jesus, the Age to Come had dawned, meaning that at last the nations (gentiles) were to be gathered into the people of God. Since the message went first to the Jews and, Paul assume, through them to the nations, Paul went to the synagogues to go to the Jews first (the biblical pattern) and also to recruit Jews to their task of bringing the good news to the Gentiles.