Sentence 1: Marcus was playing his guitar at school. 
 Sentence 3: Soon they were in a heated conversation about their music tastes 
 Sentence 4:  The duo decided that they should collaborate on some music 
 Sentence 5:  The resulting album was very popular with all of their friends 
 Option 1: His enemy Matthew approached him and began making fun of him. 
 Option 2: His friend Matthew approached him and asked about the music.