A truck carries 600 lb of Table 2 Class 3 material and 500 lb of Table 2 Class 8 material. What placarding concept applies?

1. The 1,001 lb aggregate Table 2 threshold is met
2. No placards can ever be used for mixed classes
3. Only Class 9 placards are allowed
4. Neither material alone exceeds 1,001 lb, so placards are forbidden