单选题 According to the passage, which of the following is characteristic of lipoproteins?

• (A) The dangers of lower density lipoproteins and the dangers of higher density lipoproteins are remarkably similar in the case of coronary heart disease.
• (B) A higher ratio of higher density lipoproteins to lower density lipoproteins has a salubrious effect on heart disease.
• (C) A shift from a polyunsaturated fat diet to a saturated fat diet tends to increase the risk of coronary heart disease stemming from high-density lipoproteins.
• (D) A shift from a polyunsaturated fat diet to a saturated fat diet tends to decrease the risk of coronary heart disease stemming from low-density lipoproteins.
• (E) Controlled feeding studies have yet to establish the feasibility of attempting to manipulate lipoprotein ratios through dietary change.