float compression, give output that i can't understand output confuse me

float compression, give output that i can't understand output confuse me

statements are
float a=3.2,b=4.5,c=4.9,d=4.5;
if(a == 1.1+2.1)
printf("A");
if(b == 3.2+1.3)
printf("B");
if(c == 5.7-0.8)
printf("C");
if(d == 5.5-1.0)
printf("D");
output is
BD
why not print AC.