12. An electron is trapped in an infinitely deep potential well with the width of 5 nm. When the electron is transferred from energy level E\(_2\) to E\(_1\), a photon of the wavelength 800 nm is emitted. If the width of the infinite well is increased to 10 nm, and the trapped electron is still transferred from E\(_2\) to E\(_1\), what can be the emitted photon wavelength?
(A)200 nm
(B)400 nm
(C)1600 nm
(D)3200 nm

(E)None of the above