An electron with energy E and momentum kh/2pi is incident from the left on a potential

step of height V > E at x = 0 . For x > 0 , the space part of the electron’s

wave function has the form

(A) e^ikx (B) e^ik'x; k'< k (C) e^-a x , where a is real and positive

(D) sinkx (E) identically zero

the answer given is C. but this is true only for bound state. what if it is a scattering state? then the answer should be A.

how to know about when they are asking for bound or scattering state?