[单选题]
What is the shortest-wavelength a1re mna nd7ci;1*jj7ob y*w7 X-ray photon emitted in ancnjc4qzx f 2s* ws9 /1dte4+pt X-ray tube subject to 50 k2psn9f/tjt sxwc q*4cde+41 z V?
A. $0.025 \; nm$
B. $0.25 \; nm$
C. $2.5 \; nm$
D. none of the given answers