Which of the following code will create a stacked area plot of the data in the pandas DataFrame, area_df, with a transparency value of 0.75?
a) plt.plot(area_df, kind='area', stacked=True, alpha=0.75)
b) plt.plot.area(area_df, stacked=True, alpha=0.75)
c) area_df.plot(kind='area', stacked=True, alpha=0.75)
d) area_df.plot.area(stacked=True, alpha=0.75)