The Main-Sequence Lifetime of a Star Is Given by the Equation

The main-sequence lifetime of a star is given by the equation:

A) " $\tau$ $\infty$ M/L"
B) " $\tau$ $\infty$ L/M"
C) " $\tau$ $\infty$ M ²/L"
D) " $\tau$ $\infty$ L²/L"
E) " $\tau$ $\infty$ M/L²"