Changing for my major to a minor key signature in a composition can have what affect

I think it's the last one

Explanation:

When you choose a key for your song, the main factor is usually vocal range. You don’t often have to think about whether a song is going to wind up being major or minor. That aspect usually happens with the initial creation of a song. While you might switch lyrics around, modify melodies, and change chord progressions, the fact that a song is major or minor is not something that songwriters experiment much with. Hotel California, for example, is in a minor key, and it’s hard to imagine that the writers (Felder, Henley and Frey) would have seriously tried it out in major.

But trying part of your song in minor, and then part in major, is something that’s worth experimenting with.. There are reasons you might want to do this, but the best one is that minor verses work really well when contrasted with major choruses. It’s not unusual for songs to move from minor to major. That’s because there is a psychological brightening that comes from that kind of modulation.