Jennifer
Explanation:
she has more mass which means she is using more force
They're just standing there, not going anywhere. Definitely not accelerating. That tells us that the net force on each one must be zero. So whatever push Katie is giving, she must be getting one the same size from Jennifer. And the same goes for the other lady.
What ever push she's giving her friend, her friend is also giving her.
Somehow, they're both pushing with equal forces.
