so answer is a ?It's a trick question. A coil is not straight.
IMHO, the question cannot be answered well until the problem statement is fixed. Is that really the word-for-word problem statement?
A magnetic rod is required when constructing a compass. This can be created by aligning an iron or steel rod with Earth's magnetic field and then tempering or striking it. However, this method produces only a weak magnet so other methods are preferred. For example, a magnetised rod can be created by repeatedly rubbing an iron rod with a magnetic lodestone. This magnetised rod (or magnetic needle) is then placed on a low friction surface to allow it to freely pivot to align itself with the magnetic field. It is then labeled so the user can distinguish the north-pointing from the south-pointing end; in modern convention the north end is typically marked in some way.
I think that in the end, your original answer was correct. They must have been referring to a small-diameter coil that is much longer than its diameter. It would work best if wound on a ferrous rod (that's where the "straight" part comes in, I think), since that maximizes the magnetic field that you get for a given current.
BTW, this looks like it was copy-pasted from some other source, like maybe Wikipedia? When you do that, you should always provide a link to where you copied it from. That helps to avoid copyright issues, and attribution is the right thing to do anyway.
