Which one of displayed formula below does not represent an isomer of heptane? All of these appeared to be correct. I’ve already counted their hydrogen and carbon number. Please help!

[1]: https://i.stack.imgur.com/tnQvO.jpg
The structure in the question and option (D) are the same thing. Note that a branching as apparently seems is not a real branch on the principle chain that would give an isomer. Basically (D) is same as that given in the question.