I think it would be better if this paragraph is eliminated.

Option A, added, is incorrect because the paragraph does not need to be added. It does not provide any new information or support for the main points.

Option B, improved, is incorrect because the paragraph cannot be improved. It is not necessary to the overall meaning of the text and does not add any new information or provide any support for the main points.

Option D, shortened, is incorrect because the paragraph cannot be shortened without losing its meaning. The paragraph is already very short and does not contain any unnecessary information.

Therefore, the correct answer is C. deleted.