The answer is letter C.
Protonema or Protonemata in plural form, refers to the thread-like chains of cells that form during the haploid phase of a bryophyte cycle. They give rise to gametophytes much like in the growth of moss which originates from spores that eventually develop into a leafy gametophore. Simply put, a protonema is a juvenile gametophyte that grows through an apical cell division. This then eventually grows into its adult form developing stems and leaf like structures that are photosynthetic.
