Which of the following best compares Gnetophyta and Ginkgophyta?

They both produce seeds, but gnetophytes are nonvascular and ginkgos are vascular.
They are both vascular, but gnetophytes produce flowers and fruit, and ginkgos do not.
They are both angiosperms, but gnetophytes produce cones and ginkgos produce flowers.
They are both gymnosperms, but ginkgos produce flagellated sperm and gnetophytes do not.

Best comparison for Gnetophyta and Ginkgophyta is:

They are both vascular, but gnetophytes produce flowers and fruit, and ginkgos do not.

Explanation:

Gnetophyta is a vascular seed plant that has non-motile sperm. Gnetophyta mostly grow in tropical regions and in temperate areas. They grow in the form of trees or vines which are characteristic of large leathery leaves.

Their xylem tissue consist of both tracheids and vessel elements.

Gnetophyta show a number of flowering characteristic.

Ginkgophyta is also a vascular seed plant but it has motile sperm. They are characterized by trees with distinct fan-shaped leaves. They have secondary xylem system.

Most of the species of Ginkgophyta have been extinct by now and those remaining are found in Chine only. They belong to a category of non-flowering plants.

The only species that is found now a days is Ginkgo biloba.

the answer to your question is sperm