After religious spinster's (Katharine Hepburn) missionary brother is killed in WWI Africa, dissolute steamer captain (Humphrey Bogart) offers her safe passage. She's not satisfied so she persuades him to destroy a German gunboat. The two spend most of their time fighting with each other rather than the Germans, time alone on the river leads to love
Gospel. Gospel usually contains three part harmonies(divided by Alto, Soprano, and Tenor) and emphasizes triads.
The Music Industry is containing and composing of not only companies but also individuals that making money by writing new pieces of songs, selling live shows and concerts, audio and video recordings and compositions of sheet music. These people called songwriters and composers, musicians, recorders, bandleaders, publishers, and producers, and etc.
But the companies that will be going to create, produce and distribute its musical scores are the Music Publishing companies.