If only a single member of a pair of chromosomes is present in a cell, it is a haploid condition and is most likely a reproductive cell. Diploid means that there are two sets of chromosomes, and given that here we have only one of them, naturally it cannot be diplot, but rather haploid. Also, given that it is haploid, it has to be a reproductive cell, because it consits of haploid chromosomes, whereas autosome cells consist of diploid ones.