If p,q,r are any real numbers,then a)max(p,q) < max(p,q,r) b)min(p,q)=1/2((p+q)-(p-q)) c)min(p,q) < min(p,q,r) d)none of these

d 
none are always true: 

a)max(2,2) < max(2,2,2) false they are equal
b)min(0,1)=1/2((0+1)-(0-1)) False!
c)min(2,2) < min(2,2,2) False they are equal
d)none of these