Which of the following pairs of objects would have the strongest gravitational pull?

Question

two buildings in the same city ←
two tall buildings in different cities
two stars very far away from each other
two stars very close to each other

my answer is c

Answer 1

nope, you are spot on using mass, however, close together makes gravity force much greater.

Answer 2

Which of the following pairs of objects would have the strongest gravitational pull?
two buildings in the same city ←
two tall buildings in different cities
two stars very far away from each other
two stars very close to each other
my answer is d

Answer 3

I answer D