[单选题]
What is the shortest-wavelengtw*3i1j e q.ilrs5*gxi d5)kklk knidy:/u,qczn 55 k3h X-ray photon emitted in an X-ray tube subject to 50 yn kc35ink5l )i5, sdgz/xu5kq:dk* k kV?
A. $0.025 \; nm$
B. $0.25 \; nm$
C. $2.5 \; nm$
D. none of the given answers
