[单选题]
The binding energy oyc,xxoql- zedcb/m)/k x0(,c f the :9az8)k,xova;wfh6h jv:g)o (k h- il8b hpihhydrogen atom in its ground state is -13.6 eV. What is the energy when it is in the n =-(a8bh vahh6w)g:kjf zp :, xh8io) 9vloi k;h 5 state?
A. $2.72 \; eV$
B. $-2.72 \; eV$
C. $0.544 \; eV$
D. $-0.544 \; eV$