La hamburguesa is a hamburger, and it is often accompanied by french fries -as in many other parts of the word.
However, in Spanish there is nothing French about the French fries - they are called what they are - fried potatoes (patatas fritas) or, short - papas fritas
My answer got deleted :/ but anyways, the correct answer is "las papas fritas" because: las = the, papas = potatoes, and fritas = fries. Put it together and you get potato fries aka french fries.
A simple question and I'm a Spanish speaker, so I don't see the need to explain, but here you go since apparently my previous answer wasn't enough.
