The giant redwood tree (Sequoia sempervirens) is a/an

1.  angiosperm

2.  free fern

3.  pteridophyte

4.  gymnosperm

(d) Sequoia sempervirens is a gymnspermic plant. It is a group of plants having thick, woody, branched stems. These plants also have some xeric adaptations which help them survive in adverse climatic conditions.
The other examples are incorrect because pteridophytes is primitive group, no tree is included in this. Ferns are included in Pteridophytes. Angiosperms are different form gymnosperms in seed habit and adaptations.