5. One light year is approximately equal to 94605 billion kilometers. Keeping 94605 to three significant figures, it can be expressed in scientific notation as ( ).
A. $94.60 \times 10^{3}$
B. $9.46 \times 10^{4}$
C. $0.95 \times 10^{5}$
D. $9.461 \times 10^{4}$
Reference answer: B