The correct answer is D. growing less.
The phrase “on the wane” means to be decreasing in strength, power, or popularity. In this case, the popularity of the yesterday’s superstar is decreasing. This could be due to a number of factors, such as the superstar’s age, the rise of new stars, or changes in public taste.
Option A is incorrect because it states that the popularity of the yesterday’s superstar is at its peak. This is not the case, as the popularity of the superstar is decreasing.
Option B is incorrect because it states that the popularity of the yesterday’s superstar is at rock bottom. This is also not the case, as the superstar still has some popularity, even though it is decreasing.
Option C is incorrect because it states that the popularity of the yesterday’s superstar is growing more. This is not the case, as the popularity of the superstar is decreasing.