Final answer:
Mozart died a pauper mainly due to poor financial management and declining income, exacerbated by lavish spending and changing societal support for composers.
Step-by-step explanation:
The question asks why Mozart died a pauper. The correct answer is d) Poor financial management and declining income. Mozart, despite his musical genius, struggled with financial management throughout his life. He enjoyed a lavish lifestyle and at times, extravagant spending, which contributed to his financial difficulties.
Moreover, the decline in his income was partly due to shifts in the musical tastes of the public and the decreasing patronage from the aristocracy, as the rise of the middle class brought changes in the cultural scene. Therefore, his death in a state of financial struggle was not due to his music being poorly received or solely to his medical bills, but rather to a combination of poor financial choices and changes in the societal structures that previously supported composers.