Final answer:
Venus has a density most similar to Earth, with a mass that is about 0.82 times that of Earth and an almost identical density.
Step-by-step explanation:
The planet with a density most similar to Earth is Venus (A). When comparing the densities of Earth and Venus, we see that Venus has a mass that is about 0.82 times that of Earth, with an almost identical density. This is a significant point because the average density of Venus is very close to that of Earth, making them quite similar in this aspect. In contrast, Mercury, while having a high density of 5.4 g/cm³, does not have a density similar to Earth's. Mars, with only 11% the mass of Earth, and Jupiter with its much lower average density of 1.3 g/cm³, are also not as close in density to Earth as Venus is.