How would you color the points in this scatter plot by the values of a third categorical variable, column_cat?

ggplot(data = example_df) +

 geom_point(mapping = aes(x = column1, y = column2))

		a. ggplot(data = example_df) + geom_point(mapping = aes(x = column1, y = column2, color = red))
		b. ggplot(data = example_df) + geom_point(mapping = aes(x = column1, y = column2, fill = column_cat))
		c. ggplot(data = example_df) + geom_point(mapping = aes(x = column1, y = column2), fill = column_cat)
		d. ggplot(data = example_df) + geom_point(mapping = aes(x = column1, y = column2, color = column_cat))