Pteridophytes/ ferns differ from mosses/ bryophytes in possessing
A. Independent gametophyte
B. Well developed vascular system
C. Archegonia
D. Flagella spermatozoids

Hint: Bryophytes and Pteridophytes are usually similar in many characters. Both bryophytes and pteridophytes enjoy wet, shaded environments. Both require water in order to fertilize. Sexual reproduction is oogamous in both bryophytes and pteridophytes. Both exhibit heteromorphic generational alternation. Pteridophytes and bryophytes both exhibit sporic meiosis.

Complete solution:
Let us solve this question by analyzing each of the options.
Option:A - A multicellular haploid gametophyte that produces multicellular jacketed sex organs exists in bryophytes. In pteridophytes, the gametophyte is generally independent, tiny and inconspicuous. However, the sporophytic phase of bryophytes is parasitic on the gametophytic phase, but both phases of pteridophytes are autonomous.
So, Option:A is incorrect.
Option:B – Pteridophytes have a well developed vascular system and have xylem and phloem, while bryophytes lack vascular tissues. Thus vasculature is a distinguishing feature of pteridophytes and bryophytes.
So, Option:B is correct.
Option:C – Archegonium is the female reproductive organ in ferns and mosses. So, it is not a distinguishing feature of pteridophytes and bryophytes.
So, Option:C is not correct.
Option:D – Flagellated spermatozoids are common to both pteridophytes and bryophytes. So, it is not a distinguishing feature between them.
So, Option:D is not correct.

Therefore, option B. Well developed vascular system is the correct answer.

Note:
Bryophytes are non-vascular terrestrial plants that grow in wet environments and have a multicellular diploid sporophyte that lives as a parasite on a multicellular haploid gametophyte that produces multicellular jacketed sex organs. The primary plant body of pteridophytes is a sporophyte, which is divided into real roots, stems, and leaves, whereas the gametophyte is independent, tiny and inconspicuous.