Protonema is

1.  haploid and is found in mosses

2.  diploid and is found in liverworts

3.  diploid and is found in pteridophytes

4.  haploid and is found in pteridophytes

(a) The germination of haploid spores of mosses produced by sporophyte after reduction division these haploid spores when germinate, form the Protonema. This structure later develops into an independent gametophytic plant.