Use the Properties of Logarithms to Find the Exact Value $2 \ln \mathrm { e } ^ { 4.2 }$

Multiple Choice

Use the properties of logarithms to find the exact value of the expression. Do not use a calculator.
- $2 \ln \mathrm { e } ^ { 4.2 }$

A) $2.1$
B) $e ^ { 8.4 }$
C) $8.4$
D) $4.2$