The function f(x)=ln x is transformed into the equation f(x) = 4 ln x. Select the transformation that occurred.

Vertical stretch by a factor of 4

Translating right or left we would have to have  y  = ln ( x ± b)

Translating up or down we would have to have   y = ln (x) ± c

A vertical stretch (or vertical compression )  has the form  y  =  a * ln (x)

Here,  "a"  = 4