[单选题]
Two spaceships are traf bxpkz 0b5 ov.z4y(;a0hm :fh1yp( ftveling through space at 0.60 c relative to the Earth. If the ships are headed directly toward each other, what is their approach velocity, as measured by a person oyhfpt(10 f:hm n either craft?
A. $1.2 \; c$
B. $c$
C. $0.60 \; c$
D. none of the given answers
