[单选题]
The Sun has apparent brightness ac* srw un4-d;ft Earth oruz6g5q:sn7l(l u1ob5 x*s w($1.5 \times 10^{8} \; km$ away) of B. What would be the apparent brightness of the Sun at Pluto, which is $6.0 \times 10^{9} \; km$ from the Sun?
A. $0.25 \; B$
B. $0.063 \; B$
C. $0.025 \; B$
D. $0.00063 \; B$
Post time 2024-1-22 00:41:59