Explanation:

Drosera is a partially heterotrophic plant. Let us understand the term "partially heterotrophic" before moving forward.

Heterotrophic plants are those which cannot prepare their food by photosynthesis and depend on other organisms for their nutrition. These plants obtain their nutrition by either parasitism or saprophytism.

Parasitic plants are those which obtain their nutrition from other plants. They have special structures like haustoria to penetrate the host plant's tissues and absorb nutrients from them.

Saprophytic plants are those which obtain their nutrition from dead and decaying matter.

Now, coming back to Drosera. Drosera is a carnivorous plant, which means it obtains its nutrition from insects and other small organisms. It has special structures called tentacles with sticky glandular hairs on them. When an insect lands on these leaves, the tentacles fold inwards, bringing the insect in contact with the sticky hairs. The insect gets stuck to the leaf, and the glandular hairs secrete enzymes that digest the insect's body. The nutrients obtained from the digestion are absorbed by the plant.

However, Drosera can also perform photosynthesis and prepare its food like other green plants. This is where the term "partially heterotrophic" comes into play. While it can obtain its nutrition from insects, it can also prepare its food by photosynthesis.

Therefore, option D, Drosera is the correct answer.