Which row (a, b,c or d) in the table accurately categorizes the plant as gymnosperms and angiosperms

Answer is "D".

Gymnosperms  are the plants which  produce naked seeds (unenclosed seeds). Examples are conifers, cycads, Ginkgo and gnetophytes. 

Angiosperms are flowering plants  which produce enclosed seeds. The seeds are covered by the fruit. Grains, flowering plants and fruit trees can be taken as the examples.

Ithink you should go back and learn in school rather then here asking questions

Gravitational force i believe