An upright sprinkler head is different from a pendant sprinkler head because an

The difference between an upright head and a pendent head is, an upright sprinkler is designed to be installed upright in the branchline piping of a sprinkler system. The pendent is designed to be in the pendent or 6 o clock position, with the deflector facing downward. It is important that you always install sprinklers in accordance with their designed listing.

i agree d is most definitely correct!