[单选题]
Estimate the observed wavelength for the 656 nm linvh xt61 c*nq2m lx*m :q h:q056rwmnuke in the kiu )w mq br75ukaeg.rz;88 b;spectrum of a star which is 100 million 7uz8;agk8 )bik re;.wbqr u5mlight-years from us.
A. $653 \; nm$
B. $656 \; nm$
C. $659 \; nm$
D. $692 \; nm$
