Voluntary blood donation refers to the act of selflessly dedicating one's blood to social welfare undertakings in order to save others' lives. Blood donors do not receive any remuneration from blood collection units and blood donors. Blood donation without compensation is the honor of a lifetime, and it will be respected and loved by the society. Free blood donation is a noble act of selfless dedication and saving lives, and it is the general direction of the development of blood cause in China. Blood donation is the embodiment of love and dedication. The value of relieving patients' pain and even saving patients' lives cannot be measured by money. For half a century, the age of encouraging voluntary blood donation in China is 18-55 years old, with males weighing more than 50 kg and females weighing more than 45 kg. Anyone who is healthy and passes the examination can participate in blood donation. Blood donation can be 200-400 ml each time, and the interval between two blood donations should be 6 months.
So choose: D.