Gabby was swinging on a swing. At one point while she was swinging forward, her dad gave her a push forward. She noticed that she went up higher on that swing than she had the last time she reached the top of her swing.

Why did Gabby go higher on that swing?

A. Some of her kinetic energy was lost, and that gave her more potential energy.
B. She used energy when her dad pushed her, and that energy made her go higher.
C. The work done by her dad canceled out the work done by gravity.
D. Her dad did work on her, and that work gave her more energy.