PLEASE HELP

Sara and Sam are each working on a science project in which they need to research the individual masses of the nine planets (including the dwarf planet Pluto as the ninth planet). Sara completes her data for the planets' masses in kilograms while Sam's data is in milligrams.
Sara:

Approximate how many times greater Saturn's mass is than Mercury's.

A: 2,000,000

B: 200,000

C: 20,000

D: 2,000

20,000

Explanation:

Mass of the saturn = 5.683 × 10^26

Mass of the mercury = 3.285 × 10^23

Now divide them

(5.683 × 10^26)/3.285×10^23

= 18.668.655

so approximately

it is 20,000 times greater than mercury.

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.

Iam not sure , but probably 750 or 7.5