Which statement is true? the earth has a stronger gravitational pull than the sun because it is smaller in mass. planets would travel in a straight line if it weren't for the force of the sun's gravity. the sun's gravitational pull is weaker on planets that are closer to it. the elliptical path of planets is described by newton's 1st law of motion.

I am 99% sure that A is false because the larger an object is, the stronger its gravitational pull is. I'm almost positive that's wrong.

Why? Let's think about three things: the solar system altogether, Jupiter and a black hole. Our sun has enough gravity to keep Pluto in orbit. Pluto is the furthest "planet" from the sun. It's not a planet, but you get the point. Therefore, it's clearly going to be stronger than Earth. Jupiter is our largest planet and has I believe 60 moons? I don't remember. But between Jupiter and Mars, I believe Jupiter contributes to the formation of the asteroid belt. Jupiter has a HUGE gravitational pull compared to earth. Still, not as strong as the Sun. Now a black hole, that's beyond the pull of our sun. The center of the galaxy is a supermassive black hole which is pulling ALL of the galaxy together, giving its shape and existence. How they turn into galaxies, I don't know that yet. Our earth is nothing compared to a black hole, but my point is the bigger the object, the stronger its pull.

Now onto the next one. I don't know if that's right or not, but if the sun were to disappear, our orbit would break and we'd float off into space. Straight path? Probably not but it's likely until something hits us. But it could go in a straight line. Or maybe for some reason we'd all collide. Not likely, but just a contradiction. 

C? How? The sun pulls strongest on Mercury because it's so close. When an object gets close to the sun, it pulls that object in, however, Mercury has its own pull and I believe the gravity of both objects is what balances it out. Something like that.

I don't know but the first law is an object in motion will stay in motion but I don't think that has anything to do with the shape of the paths. That has to do with gravity and distance (like Pluto's orbit is out of whack and changes distances whereas the others I believe have a constant distance).

But since the planets would float off into space without the sun, the answer is B because it's the only one that is logical. I can be wrong on my explanations because I'm no scientist but I've always enjoyed studying the solar system so I'm just giving what I know. But I hope this helps you understand.

Long story short: Your answer is B because without the sun all the objects orbiting the sun right now would float into space.