B. Apples belong to angiosperms, and have six organs: root, stem, leaf, flower, fruit and seed. B error;

C. Ginkgo biloba belongs to gymnosperms, with no flowers and bare seeds, which cannot form fruits. There are only four organs: root, stem, leaf and seed. C is wrong.

D. Pteridophytes belong to pteridophytes, with differentiated roots, stems and leaves, and conductive tissues in the body, which are generally tall and straight, and D is wrong;

So choose: a