The power radiated by a black body is $P$ and it radiates maximum energy at wavelength, ${\lambda }_0$. If the temperature of the black body is now changed so that it radiates maximum energy at wavelength $\frac{3{\lambda }_0}{4}$, the power radiated by it becomes $nP$. The value of $n$ is:

1. A
   $\frac{256}{81}$
2. B
   $\frac{4}{3}$
3. C
   $\frac{3}{4}$
4. D
   $\frac{81}{256}$