The third and fourth options lack Z space on both segments**. The second and fifth options are longer than 4h00 at DTW, and so require a fare break. The DL website will sell you these if you search multi-city instead.

The first option has only H space on both segments, meaning that the lowest pricing (one-way) fare is HAVOA0FE, a D fare. It is not sufficient to find Z space; you must find a pricing fare. Domestic I and Z fares require at least Q space or U space, respectively.

**The third is also a fare break, and the fourth is Y0 on the second segment, so the lowest pricing fare is J0FN.