R studio

In the following code, why are we using scaling?

ggplot()+geom_density(data=D,aes(x=scale(Height)))+geom_density(data=D,aes(x=scale(Weight)))+geom_density(data=D,aes(x=scale(Age)))

a.)To make three variables comparable

b.) To make the x axis look smaller

c. )To magnify non-overlapping parts of datasets