The correct option is B Protonema
Spore is the first cell of gametophytic generation. On a suitable damp habitat, a meiospore of Funaria germinates into a filamentous green alga-like structure called protonema. Protonema has green epiterranean chloronemal branches (chlornema) and non-green subterranean rhizoidal branches (caulonema). The protonema of moss, represents the juvenile stage of gametophyte.