Please select the word from the list that best fits the definition Include skin, the respiratory system, the circulatory system, and inflammation

A. antibody
B. antigen
C. Natural Defences
D. active immunity

I choose D option because may be it's correct

I believe it is c

Explanation:

because if u think about it and also do some research you would see that the circulatory system is a strong part of your body which can help u through natural defences if this sounds weird it's all in research but if it ain't c dont blame me for ruining your life- lol but yeah I think its c

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .