Can someone help turning this code into 1 single if

if(a <= 6 && a > 4)
if(b < 40)
if(b < c)
return 1;
else
return 0;
else
if(c >= a)
return 1;
else
return 0;
else
if(a == 6)
return 1;
else
if(a == 4)
if(c < b)
return 1;
else
return 0;
else
return 0;
return 0;