6.4×10−3 m6.4\times 10^{-3}\mathrm{~m}6.4×10−3 m
6.4×10−2 m6.4\times 10^{-2}\mathrm{~m}6.4×10−2 m
6.4×10−4 m6.4\times 10^{-4}\mathrm{~m}6.4×10−4 m
6.4×10−5 m6.4\times 10^{-5}\mathrm{~m}6.4×10−5 m
No correct answer\text{No correct answer}No correct answer
