Help please!
A researcher approximated the number of marigold plants in a region of desert that is roughly square shaped with a side length of 140 miles. As part of the process, she counted the number of marigold plants in a small part of the region and determined that the density of the marigold plant was about 279 plants per square mile. She assumed the density of marigold plants was the same throughout the region.

Which expression would the researcher have most likely used when making her approximation for the number of marigold plants in the square shaped region?

(3×10^2)(2×10^5)

(3×10^2)(2×10^4)

2×10^4/2×10^2

2×10^4/3×10^2