which is the correct simplification of 5.4x10^12/1.2x10^3 written in scientific notation?

a ) 4.5 x 10^7
b ) 4.5 x10^9
c ) 45 x 10^6
d ) 6.48 x 10^7

The correct simplification of 5.4x10^12/1.2x10^3 in scientific notation is:

a) 4.5 x 10^7