Which of the following self-assigned indicators are acceptable when using a phone transmission?

When operating away from your licensed location or when you want to indicate a specific operating condition (such as portable or mobile), you can append a self-assigned indicator to your call sign. In written form, this is usually indicated with a '/' character. When transmitting using voice (phone), you need a spoken word to represent this '/' character. The FCC permits the use of the words 'stroke,' 'slant,' or 'slash' to indicate this symbol over the air. Because all three spoken words are legally acceptable and widely understood in the amateur radio community, there is no single mandated word. Therefore, all of the provided choices are correct.