A.
If you work the exponents using laws of indices, they give the same result.
4.2 × 10⁹/ 1.4 x 10⁴ 4.2 × 10²/ 1.4 × 10^(-3)
using laws of indices...
since they are of the same base subtract the powers..
= 10^(9-4) = 10^(2-(-3))
= 10⁵ = 10^ (2+3) = 10⁵
B.
3.0 × 10⁵
C.
30,000.
