[单选题]
Estimate the observed wavenl4,x t5oecq/34j s1tckp ps9 lengthktxl8*hmxk1ay/1 tk 3 for the 656 nm line in the spectrum of a star which *11kkakx /3ht8txm y lis 100 million light-years from us.
A. $653 \; nm$
B. $656 \; nm$
C. $659 \; nm$
D. $692 \; nm$
