What Is the Definition of the Natural Log Function $\ln x = e ^ { x }$

Multiple Choice

What is the definition of the natural log function?

A) $\ln x = e ^ { x }$
B) $\ln x = \log _ { e } x$
C) $\ln x = \frac { 1 } { e ^ { x } }$
D) $\ln x = \log x$