1) A. Most studies look at ED, which is the persistent inability to obtain and maintain an erection. When all degrees of erectile difficulties were examined, men who did not exercise had a ten-fold increase! Get moving. Nothing beats physical activity.
2) C. Men who have ED and are under age 60, or have diabetes or high blood pressure, can have serious existing or impending heart disease. Omega-3's decrease sudden cardiac death by stabilizing heart rhythm and by increasing nitric oxide (NO) in the blood vessel lining. Obesity also increases heart rhythm problems and the chance of dying with a heart attack, and is a common cause of ED.
3) B. The usual serving of salmon contains over 1,000 mg of omega-3's, so no need for fish oil that day. Poaching is the best by avoiding toxic substances from overcooking. Grass-fed beef does have some omega-3's and L-arginine, but the saturated fat can clog the arteries and red meat increases colon cancer. You can get the L-arginine from turkey, chicken, and other sources of protein. A small part of a particular fat in walnuts is changed to the active omega-3's- better than nothing but not an effective way to get what you need.
4) C. Both. Chocolate markedly stimulates NO. It's probably not coincidental that so much is sold for Valentine's Day. The best dinner for the perfect evening (and night) would be salmon, salad with dark greens like spinach, veggies, and a chocolate desert with berries (black berries are the king of antioxidants).