Use reasoning to lead to the answer of the following question:
What has a range of sexual reproductive systems? \nOptions:\n- (A) Computer systems.\n- (B) Most plants\n- (C) animals\n- (D) Roundworms.\n- (E) mammals\n- (F) Art reproductions.\n- (G) insects\n- (H) Stuffed toy bears.

(D)
Roundworms make up the phylum Nematoda.

Within the Nematoda, a range of reproductive systems occur.

A range of reproductive systems occur in roundworms.

.

Therefore, the answer is (D)