Out of all 3 stars, the second star is the heaviest because it is 18.59 million solar masses, while Star 1 and Star 3 are 3.61 and 11.73 million in solar masses.
Also, we know that the heavier the star is, the greater the gravitational effect will have on Earth.
So with this information we know that since Star 2 is the heaviest, it will have the strongest gravitational force on Earth, then Star 3 is the second heaviest, followed by Star 1.
In conclusion, the final answer would be C. Star 2 > Star 3 > Star 1.